# CVE-2026-27628: pypdf — Fixed in 6.7.2 🐍 PyPI Not in CISA KEV # CVE-2026-27628 — pypdf [Fix: py-pdf/pypdf@f0a462d](https://github.com/py-pdf/pypdf/commit/f0a462d36971cf077d74492a348d0d06fd60ea4d) CVE-2026-27628 is a CWE-835 vulnerability in pypdf. A fix is available for pypdf — see the affected versions and patch details below. pypdf has a possible infinite loop when loading circular /Prev entries in cross-reference streams Also known as[GHSA-2rw7-x74f-jg35](/vulnerability/GHSA-2rw7-x74f-jg35)PYSEC-2026-3005 Published Feb 25, 2026 Updated Nov 4, 2026 Affected 1 pkg Patched 1 / 1 Exploits None indexed Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS) ## 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 CVE-2026-27628. ## EPSS Exploitation Probability [via FIRST.org ↗](https://www.first.org/epss/) 0.4%probability of exploitation in next 30 days Lower Risk0.00% Lower risk than most CVEs34th percentile — riskier than 34% of all scored CVEsHighest risk 0.00%0.37%0.74%1.11%0.1%0.4%May 26Sep 26Nov 26 Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.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 6.7.2, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading the file. This has been fixed in pypdf 6.7.2. As a workaround, one may apply the patch manually. ## Affected Packages 1 total 1 fixed Ecosystem Package Vulnerable range Fix 🐍PyPI `pypdf` all versions 6.7.2`pip install --upgrade 'pypdf==6.7.2'` ## Affected Products 1 product · 1 configurations Application `pypdf`py-pdf < 6.7.2 range ## Detection & mitigation playbook Open-source dependency 1. ### 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. 2. ### Fix Update pypdf to 6.7.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27628 is resolved across your whole dependency graph. 3. ### 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. ## 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 HatModerate To exploit this flaw, an attacker must be able to supply a crafted PDF file to be processed by an application using the pypdf library. This issue can cause the application to enter an infinite loop and consume a high amount of CPU resources, eventually resulting in a denial of service with no other security impact.… 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-2026-27628](https://access.redhat.com/security/cve/cve-2026-27628) (CC BY 4.0) Product Fixed in Advisory Red Hat OpenShift AI 2.25 `rhoai/odh-llama-stack-core-rhel9:1775144403` [RHSA-2026:10184](https://access.redhat.com/errata/RHSA-2026:10184) Red Hat Quay 3.10 `quay/quay-rhel8:1773971077` [RHSA-2026:5665](https://access.redhat.com/errata/RHSA-2026:5665) Red Hat Quay 3.12 `quay/quay-rhel8:1773771962` [RHSA-2026:4942](https://access.redhat.com/errata/RHSA-2026:4942) Red Hat Quay 3.15 `quay/quay-rhel8:1775169219` [RHSA-2026:6568](https://access.redhat.com/errata/RHSA-2026:6568) Red Hat Quay 3.16 `quay/quay-rhel9:1775069491` [RHSA-2026:6497](https://access.redhat.com/errata/RHSA-2026:6497) Red Hat Quay 3.16 `quay/quay-rhel9:1775169226` [RHSA-2026:6567](https://access.redhat.com/errata/RHSA-2026:6567) Red Hat Quay 3.9 `quay/quay-rhel8:1773936323` [RHSA-2026:5168](https://access.redhat.com/errata/RHSA-2026:5168) ## Frequently Asked Questions pypdf is a free and open-source pure-python PDF library. Prior to 6.7.2, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading the file. This has been fixed in pypdf 6.7.2. As a workaround, one may apply the patch manually. O3 Security · Impact-Aware SCA ### Is CVE-2026-27628 in your dependencies? Find it across PyPI, including transitive dependencies. [Scan my dependencies](/book-demo) [How O3 SCA works](/impact-aware-sca)