How severe is GHSA-rj75-hqrm-r3gf?

GHSA-rj75-hqrm-r3gf has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-rj75-hqrm-r3gf?

GHSA-rj75-hqrm-r3gf affects the following packages: postcss-selector-parser (npm). Ecosystems affected: npm.

How do I fix GHSA-rj75-hqrm-r3gf?

Update postcss-selector-parser to 7.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rj75-hqrm-r3gf is resolved across your whole dependency graph.

How do I detect GHSA-rj75-hqrm-r3gf in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for postcss-selector-parser, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-rj75-hqrm-r3gf if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-rj75-hqrm-r3gf actively exploited in the wild?

No public exploit code has been indexed for GHSA-rj75-hqrm-r3gf yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-rj75-hqrm-r3gf?

GHSA-rj75-hqrm-r3gf has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 32th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-rj75-hqrm-r3gf?

GHSA-rj75-hqrm-r3gf is classified as Uncontrolled Resource Consumption (CWE-400), CWE-407 (CWE-407). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-rj75-hqrm-r3gf published, and has it been updated?

GHSA-rj75-hqrm-r3gf was published on October 5, 2026 and was last updated on October 5, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

PostCSS: Quadratic complexity in flat selector parsing allows CPU exhaustionGHSA-rj75-hqrm-r3gf

MEDIUMFix: postcss/postcss-selector-parser@62b1917

GHSA-rj75-hqrm-r3gf is a medium-severity (CVSS 5.9) Uncontrolled Resource Consumption vulnerability in postcss-selector-parser. A fix is available for postcss-selector-parser — see the affected versions and patch details below.

Also known asCVE-2026-104844

Published

Oct 5, 2026

Updated

Oct 5, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-rj75-hqrm-r3gf.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs32th percentile — riskier than 32% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

GHSA-rj75-hqrm-r3gf by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

2Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

postcss-selector-parsernpm

88.2Mdownloads / week

Description

Impact

. and # are not word delimiters in the tokenizer, so a flat selector such as .a.a.a... reaches splitWord() as a single word token carrying n class or id indexes. Three passes scanned those index arrays linearly for every index, making the parse O(n^2) in the number of indexes rather than in input length: uniqs(), the indices.forEach loop, and the Sass-interpolation filter. Parsing a 400 KB flat selector took ~34 s on a modern laptop, fully occupying a single thread. A benign selector of identical byte size parses in tens of milliseconds, so the cost is driven by the index count, not the input size. The nesting depth of such a selector is 0, so the maxNestingDepth guard added in 7.1.3 offers no protection.

Reachability is deployment dependent. Only consumers that parse untrusted, attacker-supplied selectors synchronously in a request path are exposed, for example CSS sanitizers, CSS-in-JS services and online playgrounds. Ordinary build-time use on trusted sources is not affected.

Patches

Fixed in 7.1.6. The three passes now use Set membership tests, making parsing linear in the number of indexes. There is no behaviour change: parsing is byte-identical on a differential corpus of 8413 selectors.

Workarounds

Cap the size of selectors accepted from untrusted sources before parsing.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`postcss-selector-parser`	all versions	7.1.6`npm install postcss-selector-parser@7.1.6`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for postcss-selector-parser, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update postcss-selector-parser to 7.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rj75-hqrm-r3gf is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact `.` and `#` are not word delimiters in the tokenizer, so a flat selector such as `.a.a.a...` reaches `splitWord()` as a single word token carrying n class or id indexes. Three passes scanned those index arrays linearly for every index, making the parse O(n^2) in the number of indexes rather than in input length: `uniqs()`, the `indices.forEach` loop, and the Sass-interpolation filter. Parsing a 400 KB flat selector took ~34 s on a modern laptop, fully occupying a single thread. A benign selector of identical byte size parses in tens of milliseconds, so the cost is driven by the ind