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WordPress: Unauthenticated path traversal leading to conditional RCE

94 points4 hoursgithub.com
zelphirkalt2 hours ago

These are the reason, why every easily reachable web server will be spammed with /something/something.php?somearg=someval. If I had to guess, which software on the web has been the most exploitable over all of the web's history, WP would surely be among the top candidates. Maybe right after MS Teams or Sharepoint or some stuff like that.

toyg1 hour ago

TBF, some of it is structural: if you're the most popular anything on the internet, you'll be the most attacked and the most exploited, and hence the most exploitable.

formerly_proven46 minutes ago

nginx serves a third of web traffic.

tommica23 minutes ago

Nginx also has cves.

Retr0id55 minutes ago

That's not really true.

traceroute662 hours ago

> WP would surely be among the top candidates

And its closely related cousin, Joomla.

bombcar1 hour ago

Joomla makes WP look like Fort Knox.

nom1 hour ago

The access log of public http servers is truly interesting to watch.

You know that the scripts doing it are optimized for success rate, so the types of requests they send give you an impression of what's actually out there.

It's clear to me that once we finally achieve rogue AGI, it is going to propagate through unpatched WordPress WooCommerce instances.

mitxela47 minutes ago

Not success rate per request though.

reaperducer1 hour ago

If I had to guess, which software on the web has been the most exploitable over all of the web's history, WP would surely be among the top candidates.

People on HN love to talk smack about WordPress. After all these years, it's as much a reflex as shouting "walled garden!" every time there's an Apple story.

Yet some of the biggest web sites on the internet run WordPress, and more importantly, some of the biggest hacking targets on the internet run WordPress.

Prime example: whitehouse.gov.

If you know what you're doing, WordPress fine. The same is true with every other piece of technology out there.

But people on HN like to lump the good in with the bad because everything is binary.

nkozyra38 minutes ago

> If you know what you're doing, WordPress fine

If you know what you're doing, a loaded gun without a safety is fine, too. But you have the option, why not pick the unloaded one with a safety mechanism?

spogbiper45 minutes ago

> If you know what you're doing, WordPress fine.

Probably true, but for whatever reason Wordpress seems to attract an awful lot of people that do not know what they are doing

zelphirkalt24 minutes ago

I think the problem is of another nature:

People who _don't_ know what they are doing are using WP for every project, that they touch, because it is all they know. Given WPs database design, the assumptions baked into that, and the complications resulting from that, make anything other than a posts and pages website a PITA.

This in turn requires one to install shitty plugins, or spend time developing a minimalistic solution to each new challenge. With every plugin the attack surface grows, and the vast majority of larger WP sites is this cobbled together mess of WP plugins, having some WP expert trying to make them all work together without stepping on each other's toes, while hopelessly falling behind on updates, because updates could, and _will_ break things.

People only knowing PHP and WP, try to use WP as a sledgehammer, not realizing that hammer actually being made out of glass. Very few plugins are actually minimalistic, no-bloat, safe, well-developed. Lots of those plugins are 80% marketing fluff and wanting to make a business out of worse than mediocre code bases. That's also due to many people in that community being exactly those, who don't know anything but WP.

Even normal core WP updates can break the legality of ones site. I have had that at some point, where after some WP update it started loading emojis from a friggin third party, to replace the unicode symbol I had used. I was furious, because this needs to be part of the data protection policies/statements. One does not simply load a third party shit, replacing what the dev actually put there, which was just a unicode symbol. That's an idiotic thing to do. If I wanted third-party emojis, I would have included them myself.

Finally, some big pages run on WP says not much, given the catastrophic state of many websites. whitehouse.gov is laughably badly made. Another complete failure. The first thing I see that it loads Google tags manager. A government site loading shit.

    fonts.googleapis.com
    googletagmanager.com
    gstatic.com
    parsely.com
All this crap. And this is only what is loaded right out of the box. I haven't even allowed their shitty scripts to run yet.

And the navigation font is tiiiny. What a horrendous design.

When I click on some navigation link, it wants to go to:

    https://www.whitehouse.gov/wp-content/uploads/2026/01/Wide_Site_Primary_02.mp4
lol. From nav directly to some mp4 video?? Not a URL of a page, which then would display the video, but a URL directly to a video? Good that my noscript blocked media on that domain!

If it is a prime example, then it is a prime example of a very shitty made website, by people, who don't know what they should be doing.

So all this shows is one can make a shitty site using WP. Great. I am sure one can also make a not shitty site using WP. Like you say, _"If you know what you are doing ..."_. Just that most WP people don't. They don't know how to not make a mess, or choose the short-term easy way out, and install tons of shitty plugins. Many of them just have to put things up once initially and are paid, or hold the hand open for some maintenance fee they extract, required only due to how badly made these WP sites are.

BorisMelnik29 minutes ago

to be fair it is one of the top CMS's on the web (probably won't be in 2027) and its PHP / Mysql which in history have been very exploitable.

random_savv2 hours ago

I am so happy that I asked Codex to rewrite our website as Hugo templates which allowed us to statically host it and get rid of Wordpress. So much stress gone!

woah1 hour ago

You can make the most intricate drag and drop admin interfaces to allow the editor to customize everything, and they will still call you to put up every post, so might as well go static

themeiguoren34 minutes ago

Is there a good replacement for wordpress comments? That's the one thing holding me back from porting at the moment.

janvdberg26 minutes ago
iLoveOncall26 minutes ago

I think you can render Disqus on static websites, but Disqus is its own piece of crap so not sure you'd want to.

toast01 hour ago

When I finally got approval to rewrite the company blog from Wordpress into something that was mostly static, it was the best week. I used PHP to do mobile/desktop and language selection, because PHP is pretty useful, and it can be pretty fast and secure if you only do simple things.

Never had to worry again about sequencing updates where the update changed the database schema and I had a cluster of 6 web servers. Never had to worry anymore about long ass load times because the web servers were in 3 colos and wordpress wouldn't play nice with local read only mysql replicas. No more worries about why pingbacks and comments keep showing up in the database even those those features were turned off; at least they weren't showing up in a moderation queue, but still.

vntok2 hours ago

Sorry in advance if you were joking, but for readers who aren't in the know: Hugo had, in fact, two 9.3 CVSS vulnerabilities just 11 days ago...

https://app.opencve.io/cve/CVE-2026-89259

https://app.opencve.io/cve/CVE-2026-89258

abound1 hour ago

To be clear, those are CVEs in the tooling, not in the generated static sites. Not great, but very different from this WordPress CVE

jklinger41027 minutes ago

This thread is fucking unhinged

bakugo1 hour ago

It's crazy to me that WP still doesn't make use of proper function type declarations, 11 years after they were added to PHP.

iLoveOncall1 hour ago

WordPress really is a piece of garbage software, and if you've ever developed plugins for it it is soooo apparent.

The documentation is a perfect reflection of the absolute mess of spaghetti code that it is, half of the methods that you will use constantly when developing plugins are undocumented, even untyped. It's literally unusable.

I know WordPress is good thanks to its ecosystem, but really, really, do NOT use it.

vntok3 hours ago

Ironically, this 9 years old comment on the official documentation page of one of the affected functions perfectly describes both the nature and remediation of this major security flaw:

> Paul Ryan 9 years ago

> Note that locate_template() does not prevent directory traversal attacks, so if you’re passing a user-provided template name to the function, be sure to verify that it’s from one of the three appropriate locations (active theme directory, parent theme directory, or /wp-includes/theme-compat/ directory).

https://developer.wordpress.org/reference/functions/locate_t...

foul3 hours ago

Ahahah I remember to have patched themes for clients by hand, years ago. A different time, where a core team would for whatever reason leave security holes around to be sure you need three frameworks around their pile of dung code.

whycome3 hours ago

hmm, this may be why i just saw an unexpected update to a very old theme.

patrickdavey2 hours ago

It's not clear to me: do we need to both apply the patch _and_ check if our themes are vulnerable, or just apply the patch?

Edit: looking at the patch itself it looks like it fixes the root cause and so it shouldn't matter what themes are doing themselves. But possibly I'm reading it incorrectly.

system23 hours ago

pearcmd.php must exist, and register_argc_argv must be on, not common with hosting providers. But I am assuming the other themes and meeting conditions possibly affect a lot of WordPress sites.

dofm3 hours ago

As the article points out, one issue is that the official Docker container for PHP has this configuration.

However at least in principle all of the affected versions [0] could be automatically updated. Not sure if they have set it to auto-update as far back as 4.7 though.

[0] except 4.9.3 which has a bug in its automatic update mechanism.

foul3 hours ago

pearcmd and register_argc_argv are just examples. get_page_template was unsanitized in some themes, that's the flaw, you could then combine it with one of a million unauthorized file upload in wordpress plugins to try and eval code. An attacker would like to use upload + this chain of requires (instead of just uploading a php) because of hardened configuration and the pwn can go unnoticed in the logs.

Also, with pearcmd (if you can get to that, there's no open_basedir) and containers a novice sysadmin will publish insecure sites.

tptacek3 hours ago

[flagged]

dofm3 hours ago

Not sure if it’s a couple. Devs routinely make heavily edited copies of the core themes so there will be many, many unpublished themes that use the “page-“ prefix for templates; it was (is?) a reasonably common convention.

(No particular disagreement with the rest of your comment though)

paulez3 hours ago

This score specifically means that given some specific conditions, anyone can execute code over the network on a vulnerable WordPress setup. Is this not true?

tptacek3 hours ago

I'm not saying that the vulnerability isn't severe or important to people running Wordpress, only that CVSS scores are literally a Ouija Board that can come out to whatever the user wants them to.

ferngodfather2 hours ago

Yeah give me a vuln and I can make it anything between a 2 and 8 quite easily. I routinely see 10s that are "Critical 10.0 CVE (but only if you're using X language with X setting changed from default, and the attacker can MiTM your traffic)"

nicce3 hours ago

> CVSS scores are literally a Ouija Board that can come out to whatever the user wants them to.

Not really. They are very good at describing the technical impact. Sometimes pre-condition is very rare and that reduces overall likelihood but for those few it applies, the impact still could be catastrophic. Who wants to risk it if whole business could go down?

+2
akerl_3 hours ago
bombcar3 hours ago

My assumption is that any Wordpress setup whatsoever allows anyone to execute code remotely.

6c696e75782 hours ago

Indeed, it's a foothold into a network.

vntok3 hours ago

> This is a somewhat situational Wordpress RCE that impacts only a couple themes. reply

That is dangerously incorrect, a whole lot of themes are vulnerable. The main pre-condition, "presence of a top-level directory named 'page-xxx' like 'page-templates' in the theme's directory" is actually an official recommendation in the WordPress documentation.

See here: https://developer.wordpress.org/themes/classic-themes/templa...

> As discussed in Organizing Theme Files, WordPress can recognize page templates stored in the theme’s root folder or in a first-level subdirectory of the theme folder. *The page-templates/ folder is a common convention* for organizing global page templates, but it is not required. Page templates can also be stored in other first-level subdirectories, such as templates/ or page_templates/.

dawnerd2 hours ago

Yeah not sure why you’re being downvoted when the built in themes are vulnerable as is the default docker image pre php8.5 which a lot of people use as a base and I bet a lot of hosting providers use as well behind the scenes.

TZubiri2 hours ago

It's crazy how many users are standing by this take. Not only is a 9.8 CVSS critical, even if it doesn't affect your config, you should trash any dependency that has so many 9+CVSS vulns that you become numb to them.

When you use a dependency and a 9+CVSS vuln comes out, you read it and respect it. If you come to the conclusion that CVSS don't mean anything because there's just so many vulns, that's saying something of the dependency and your security posture.

Burn Wordpress with a flemmenwerfer, or build a hard virtualization layer around it, give it its own scoped certs, your Wordpress things will get hacked, especially if they use plugins.