CVE-2023-36810: pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF

Q: How do I fix CVE-2023-36810?

pypdf: upgrade to newer than 1.27.8. Exact commands for each OS are on this page.

Q: Is CVE-2023-36810 being exploited?

CVE-2023-36810 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-36810 affect?

CVE-2023-36810 affects pypdf. Severity is medium (CVSS 6.2). pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. An attacker who uses this vulnerability can craft a PDF which leads to unexpected long runtime. This quadratic runtime bloc

Q: How urgent is CVE-2023-36810?

Priority 39/100. Public exploit reference

Routine

MEDIUM 6.2UPGRADE

CVE-2023-36810 is a medium-severity flaw (CVSS 6.2) affecting pypdf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. An attacker who uses this vulnerability can craft a PDF which leads to unexpected long runtime. This quadratic runtime blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. This issue has been addressed in PR 808 and versions from 1.27.9 include this fix. Users are advised to

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.2 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-407
Published	2023-06-30
Last modified	2026-11-02

Publisher (CNA): GitHub, Inc. · Vendor: py-pdf

Last updated 2026-11-02 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-06-30 19:15 UTCPublished CVE record published
2026-11-02 16:06 UTCUpdated Record last modified

py-pdf pypdf UPGRADE

Affected: <= 1.27.8

Fixed in: newer than 1.27.8

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy pypdf || rpm -q pypdf || pypdf --version

2. UPGRADE to newer than 1.27.8 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade pypdf

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pypdf

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-36810?

pypdf: upgrade to newer than 1.27.8. Exact commands for each OS are on this page.

Is CVE-2023-36810 being exploited?

CVE-2023-36810 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-36810 affect?

CVE-2023-36810 affects pypdf. Severity is medium (CVSS 6.2). pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. An attacker who uses this vulnerability can craft a PDF which leads to unexpected long runtime. This quadratic runtime bloc

How urgent is CVE-2023-36810?

Priority 39/100. Public exploit reference

Software pages

Python vulnerabilities

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References

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