How severe is GHSA-5849-834g-hvw5?

No CVSS score has been assigned to GHSA-5849-834g-hvw5 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-5849-834g-hvw5?

GHSA-5849-834g-hvw5 affects the following packages: pypdf (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-5849-834g-hvw5?

Update pypdf to 6.21.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5849-834g-hvw5 is resolved across your whole dependency graph.

How do I detect GHSA-5849-834g-hvw5 in my PyPI dependencies?

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

How do I mitigate GHSA-5849-834g-hvw5 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-5849-834g-hvw5 actively exploited in the wild?

No public exploit code has been indexed for GHSA-5849-834g-hvw5 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-5849-834g-hvw5?

GHSA-5849-834g-hvw5 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th 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-5849-834g-hvw5?

GHSA-5849-834g-hvw5 is classified as CWE-835 (CWE-835). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-5849-834g-hvw5 published, and has it been updated?

GHSA-5849-834g-hvw5 was published on October 30, 2026 and was last updated on October 30, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

pypdf has possible infinite loop when hitting EOF in standard xref table during trailer searchGHSA-5849-834g-hvw5

Fix: py-pdf/pypdf#4289

GHSA-5849-834g-hvw5 is a CWE-835 vulnerability in pypdf. A fix is available for pypdf — see the affected versions and patch details below.

Also known asCVE-2026-119203

Published

Oct 30, 2026

Updated

Oct 30, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 30, 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-5849-834g-hvw5.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs23th percentile — riskier than 23% of all scored CVEsHighest risk

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

Real-World Exposure

1 pkg affected

🐍pypdf

Real-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

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.4, pypdf can enter an infinite loop while opening a crafted incomplete PDF whose standard cross-reference table reaches the end of the file without a trailer. The trailer search can repeatedly rewind to the same stream position instead of terminating when parsing makes no progress, blocking the processing thread. This issue is fixed in version 6.21.4.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`pypdf`	all versions	6.21.4`pip install --upgrade 'pypdf==6.21.4'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pypdf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pypdf to 6.21.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5849-834g-hvw5 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 An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires opening an incomplete file without a `trailer`. ### Patches This has been fixed in [pypdf==6.21.4](https://github.com/py-pdf/pypdf/releases/tag/6.21.4). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#4289](https://github.com/py-pdf/pypdf/pull/4289).

O3 Security · Impact-Aware SCA

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