CVE-2026-6238: The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.0.1 to version 2

Routine

MEDIUM 6.5REMOTEMITIGATE

CVE-2026-6238 is a medium-severity flaw (CVSS 6.5) affecting glibc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.0.1 to version 2.43 fail to validate the RDATA content against the RDATA length in a DNS response when processing A6, CERT, LOC, TKEY or TSIG records, which may allow an attacker to craft a DNS response, causing a target application to crash or read uninitialized memory. These functions are for application debugging only and hence not in the path of cod

Why this priority

Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-126
Published	2026-04-28
Last modified	2026-07-14

Publisher (CNA): GNU C Library · Vendor: gnu

Last updated 2026-07-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-28 19:37 UTCPublished CVE record published
2026-07-14 13:19 UTCUpdated Record last modified

gnu glibc MITIGATE

Affected: >= 2.2

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

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

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Downgrade not recommended

This is a core system component: downgrading can break the OS. Apply the distro update or the vendor mitigation.

Advisories and coverage

Official advisories

AlmaLinux Errata: [ALSA-2026:42952] Moderate: glibc security update 2026-07-23

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-2026-6238?

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

Is CVE-2026-6238 being exploited?

CVE-2026-6238 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-2026-6238 affect?

CVE-2026-6238 affects glibc. Severity is medium (CVSS 6.5). The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.0.1 to version 2.43 fail to validate the RDATA content against the RDATA length in a DNS response when processing A6, CERT, LOC, TKEY or TSIG reco

How urgent is CVE-2026-6238?

Priority 35/100. Remotely exploitable, no login, no user action

Software pages

glibc vulnerabilities

Related CVEs

CVE-2026-5435 HIGH 7.3 MITIGATE The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.2 and newer fail
CVE-2026-4046 HIGH 7.5 UPGRADE The iconv() function in the GNU C Library versions 2.43 and earlier may crash due to an assertion failure when

References

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