How severe is CVE-2026-102997?

No CVSS score has been assigned to CVE-2026-102997 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-102997?

Affected package information for CVE-2026-102997 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-102997?

No fixed release is recorded for CVE-2026-102997 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2026-102997 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2026-102997 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 CVE-2026-102997 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-102997 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 CVE-2026-102997?

CVE-2026-102997 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 21th 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 CVE-2026-102997?

CVE-2026-102997 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 CVE-2026-102997 published, and has it been updated?

CVE-2026-102997 was published on September 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.

CVE-2026-102997: Py-pdf

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 CVE-2026-102997.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs21th percentile — riskier than 21% of all scored CVEsHighest risk

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

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.

Affected Products

1 product · 1 configurations

Application

pypdfpypdf_project

< 6.18.1

range

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2026-102997 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
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.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This Important impact flaw can consume excessive processing time when a Red Hat service decodes a malformed FlateDecode stream in a crafted PDF.

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for CVE-2026-102997 (CC BY 4.0)

Frequently Asked Questions

pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.

O3 Security · Impact-Aware SCA

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CVE-2026-102997 — Py-pdf