CVE-2026-27888: pypdf is a free and open-source pure-python PDF library

Q: How do I fix CVE-2026-27888?

pypdf: upgrade to 6.7.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-27888 being exploited?

CVE-2026-27888 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-2026-27888 affect?

CVE-2026-27888 affects pypdf. Severity is high (CVSS 7.5). pypdf is a free and open-source pure-python PDF library. Prior to 6.7.3, an attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing the `xfa` property of a reader or writer and th

Q: How urgent is CVE-2026-27888?

Priority 40/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADE

CVE-2026-27888 is a high-severity flaw (CVSS 7.5) affecting pypdf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.3, an attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing the `xfa` property of a reader or writer and the corresponding stream being compressed using `/FlateDecode`. This has been fixed in pypdf 6.7.3. As a workaround, apply the patch manually.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-400
Published	2026-02-26
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

2026-02-26 01:16 UTCPublished CVE record published
2026-11-02 16:06 UTCUpdated Record last modified

py-pdf pypdf UPGRADE

Affected: < 6.7.3

Fixed in: 6.7.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 6.7.3 (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-2026-27888?

pypdf: upgrade to 6.7.3. Exact commands for each OS are on this page.

Is CVE-2026-27888 being exploited?

CVE-2026-27888 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-2026-27888 affect?

CVE-2026-27888 affects pypdf. Severity is high (CVSS 7.5). pypdf is a free and open-source pure-python PDF library. Prior to 6.7.3, an attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing the `xfa` property of a reader or writer and th

How urgent is CVE-2026-27888?

Priority 40/100. High severity; Remotely exploitable, no login, no user action

Software pages

Python vulnerabilities

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References

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