CVE-2026-79771: Nokogiri versions before 1.19.3 contain a memory leak in the XSLT Stylesheet transform method when processing

Q: How do I fix CVE-2026-79771?

nokogiri: upgrade to 1.19.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-79771 being exploited?

CVE-2026-79771 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-2026-79771 affect?

CVE-2026-79771 affects nokogiri. Severity is medium (CVSS 5.3). Nokogiri versions before 1.19.3 contain a memory leak in the XSLT Stylesheet transform method when processing Ruby strings containing null bytes. Attackers can exploit this by passing attacker-controlled input with null bytes to transform p

Q: How urgent is CVE-2026-79771?

Priority 33/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-79771 is a medium-severity flaw (CVSS 5.3) affecting nokogiri. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Nokogiri versions before 1.19.3 contain a memory leak in the XSLT Stylesheet transform method when processing Ruby strings containing null bytes. Attackers can exploit this by passing attacker-controlled input with null bytes to transform parameters, causing heap allocations to leak and enabling denial of service against long-running processes.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 64%)
CISA exploited list	No
Weakness	CWE-401
Published	2026-08-25
Last modified	2026-09-01

Publisher (CNA): VulnCheck · Vendor: nokogiri

Last updated 2026-09-01 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-25 16:17 UTCPublished CVE record published
2026-09-01 14:55 UTCUpdated Record last modified

nokogiri nokogiri UPGRADE

Affected: < 1.19.3

Fixed in: 1.19.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 1.19.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nokogiri

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-2026-79771?

nokogiri: upgrade to 1.19.3. Exact commands for each OS are on this page.

Is CVE-2026-79771 being exploited?

CVE-2026-79771 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-2026-79771 affect?

CVE-2026-79771 affects nokogiri. Severity is medium (CVSS 5.3). Nokogiri versions before 1.19.3 contain a memory leak in the XSLT Stylesheet transform method when processing Ruby strings containing null bytes. Attackers can exploit this by passing attacker-controlled input with null bytes to transform p

How urgent is CVE-2026-79771?

Priority 33/100. Remotely exploitable, no login, no user action

Software pages

Ruby vulnerabilities

Related CVEs

CVE-2026-57235 HIGH 8.2 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language
CVE-2026-57236 HIGH 8.2 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language
CVE-2026-57434 HIGH 7.5 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language
CVE-2026-57435 HIGH 7.5 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language
CVE-2026-57436 MEDIUM 5.3 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language

References

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