GHSA-2f54-p244-32q6 is a medium-severity (CVSS 6.5) CWE-1333 vulnerability in open-webui. A fix is available for open-webui — see the affected versions and patch details below.
Open WebUI: Any authenticated user can stall a worker via a knowledge-search pattern that backtracks catastrophically
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-2f54-p244-32q6.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-2f54-p244-32q6 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
open-webuiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
The built-in knowledge search tools let a chat participant choose the pattern used to grep knowledge files. Patterns containing regex metacharacters were compiled with Python's backtracking re engine and run against every line of every reachable file, with no time limit anywhere on that path. A single crafted pattern and a single short line of matching text pin one CPU core for as long as the attacker wants, and because the search runs synchronously inside the event loop, that worker serves nobody else while it spins.
Preconditions
- Default configuration. The knowledge builtin tool group is enabled by default, and with
ENABLE_KB_EXECat its default ofFalsethe model is handedgrep_knowledge_files, which is the affected path. - Any authenticated user, no elevated role and no workspace permission.
- One file the attacker can read.
USER_PERMISSIONS_CHAT_FILE_UPLOADdefaults to true and a user always has read access to their own upload, so both halves of the input are attacker-supplied. - A model willing to call the tool with the attacker's literal pattern. This is the one non-deterministic step: it is reliable in practice by instructing the model in your own chat, but it is not guaranteed on a given turn.
- Deployments running with
UVICORN_WORKERSat its default of 1 lose the whole instance; multi-worker deployments lose one worker per request.
Impact
Availability, against every other user of the affected worker. Cost scales exponentially with the length of the matching text: measured on the vulnerable code, a 24 character subject takes 1.2s, 28 takes 19s and 30 takes 74s, and a 40 character subject extrapolates to roughly a day of CPU. The same subject against a literal pattern takes under a microsecond. There is no confidentiality or integrity effect, and no data is read or altered.
Fix
Fixed in 0.11.0 by https://github.com/open-webui/open-webui/pull/27471. Pattern matching moved from re to the regex engine, which supports a per-search timeout, and every tool call now runs its searches under a single 2 second matching budget, after which the tool returns an error instead of continuing to match. Upgrading is sufficient; there is nothing an operator has to configure.
Root cause
backend/open_webui/tools/knowledge_fs.py,build_matcher: compiled the caller's pattern and returned an unbounded match function.backend/open_webui/tools/builtin.py,grep_knowledge_files: the default-configuration caller, which ran that matcher over every line of every reachable file.
build_matcher treated any pattern containing regex metacharacters as a regex, so no explicit flag was needed to reach the compiler. From there the only limits in place were on results, not on work: a cap on matches returned and a cap on files scanned, neither of which bounds the time a single line can consume. Backtracking cost is exponential in the length of the matched text rather than in the pattern, so capping pattern length or line length would not have bounded it either. The engine had no timeout available and none was imposed elsewhere.
Proof of concept
Against a real instance as an ordinary user:
- Upload a text file whose content is a single line of 30
xcharacters, and noy. - In a chat on a model with the knowledge tools available, instruct the model to call
grep_knowledge_fileswith the pattern(x|x)*yand that file's id. - The request never returns. The worker's CPU sits at 100% for the duration, and concurrent requests from other users on the same worker do not complete.
Growth measured directly against build_matcher on the vulnerable code:
| subject length | time |
|---|---|
| 16 | 4.7ms |
| 20 | 73ms |
| 24 | 1.21s |
| 28 | 19.3s |
| 30 | 73.9s |
Credits
@Classic298, for the finding and the fix.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | open-webui | ≥ 0.9.6&&< 0.11.0 | 0.11.0pip install --upgrade 'open-webui==0.11.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for open-webui, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update open-webui to 0.11.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2f54-p244-32q6 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-2f54-p244-32q6 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-2f54-p244-32q6. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-2f54-p244-32q6 in your dependencies?
O3 Security finds GHSA-2f54-p244-32q6 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.