CVE-2023-3436: Xpdf 4.04 will deadlock on a PDF object stream whose "Length" field is itself in another object stream.

Routine

LOW 3.3DOWNGRADE

CVE-2023-3436 is a low-severity flaw (CVSS 3.3) affecting xpdf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Xpdf 4.04 will deadlock on a PDF object stream whose "Length" field is itself in another object stream.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	3.3 (Low)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 93%)
CISA exploited list	No
Weakness	CWE-833, CWE-667
Published	2023-06-27
Last modified	2026-06-17

Publisher (CNA): Glyph & Cog, LLC · Vendor: xpdfreader

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-06-27 21:15 UTCPublished CVE record published
2026-06-17 06:14 UTCUpdated Record last modified

xpdfreader xpdf DOWNGRADE

Affected: 4.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.04

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 4.04 (Debian / Ubuntu)

apt-cache madison xpdf sudo apt install xpdf=<VERSION_BEFORE_4.04> sudo apt-mark hold xpdf

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list xpdf sudo dnf downgrade xpdf-<VERSION_BEFORE_4.04> sudo dnf versionlock add xpdf

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2023-3436?

xpdf: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-3436 being exploited?

CVE-2023-3436 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-2023-3436 affect?

CVE-2023-3436 affects xpdf. Severity is low (CVSS 3.3). Xpdf 4.04 will deadlock on a PDF object stream whose "Length" field is itself in another object stream.

How urgent is CVE-2023-3436?

Priority 13/100. No elevated risk signals yet.

Related CVEs

CVE-2024-7868 HIGH 8.2 UPGRADE In Xpdf 4.05 (and earlier), invalid header info in a DCT (JPEG) stream can lead to an uninitialized variable i
CVE-2024-7867 MEDIUM 6.2 UPGRADE In Xpdf 4.05 (and earlier), very large coordinates in a page box can cause an integer overflow and divide-by-z
CVE-2024-7866 MEDIUM 5.5 UPGRADE In Xpdf 4.05 (and earlier), a PDF object loop in a pattern resource leads to infinite recursion and a stack ov
CVE-2024-4568 LOW 2.9 UPGRADE In Xpdf 4.05 (and earlier), a PDF object loop in the PDF resources leads to infinite recursion and a stack ove
CVE-2024-4141 LOW 2.9 UPGRADE Out-of-bounds array write in Xpdf 4.05 and earlier, triggered by an invalid character code in a Type 1 font

References

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