CVE-2021-3508: A flaw was found in PDFResurrect in version 0.22b

Routine

MEDIUM 5.5DOWNGRADE

CVE-2021-3508 is a medium-severity flaw (CVSS 5.5) affecting pdfresurrect. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in PDFResurrect in version 0.22b. There is an infinite loop in get_xref_linear_skipped() in pdf.c via a crafted PDF file.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Weakness	CWE-835
Published	2021-04-28
Last modified	2026-06-17

Publisher (CNA): Fedora Project · Vendor: pdfresurrect project

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

Am I affected?

Timeline

2021-04-28 14:15 UTCPublished CVE record published
2026-06-17 04:05 UTCUpdated Record last modified

pdfresurrect project pdfresurrect DOWNGRADE

Affected: 0.22b

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.22b

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.22b (Debian / Ubuntu)

apt-cache madison pdfresurrect sudo apt install pdfresurrect=<VERSION_BEFORE_0.22b> sudo apt-mark hold pdfresurrect

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

dnf --showduplicates list pdfresurrect sudo dnf downgrade pdfresurrect-<VERSION_BEFORE_0.22b> sudo dnf versionlock add pdfresurrect

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-2021-3508?

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

Is CVE-2021-3508 being exploited?

CVE-2021-3508 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-2021-3508 affect?

CVE-2021-3508 affects pdfresurrect. Severity is medium (CVSS 5.5). A flaw was found in PDFResurrect in version 0.22b. There is an infinite loop in get_xref_linear_skipped() in pdf.c via a crafted PDF file.

How urgent is CVE-2021-3508?

Priority 37/100. Public exploit reference

Related CVEs

CVE-2020-9549 HIGH 7.8 UPGRADE MITIGATE In PDFResurrect 0.12 through 0.19, get_type in pdf.c has an out-of-bounds write via a crafted PDF document.
CVE-2020-20740 HIGH 7.8 UPGRADE MITIGATE PDFResurrect before 0.20 lack of header validation checks causes heap-buffer-overflow in pdf_get_version().
CVE-2019-14934 HIGH 7.8 UPGRADE MITIGATE An issue was discovered in PDFResurrect before 0.18
CVE-2019-14267 HIGH 7.8 DOWNGRADE MITIGATE PDFResurrect 0.15 has a buffer overflow via a crafted PDF file because data associated with startxref and %%EO

References

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