What’s Vulnerable › Vulnerabilities

CVE-2026-6238: Buffer overread in ns_printrrf with corrupted RDATA field

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-28 · updated 2026-07-14
• Weakness: CWE-126

Description

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 code executed by the DNS resolver. Further, they have been deprecated since version 2.34 and should not be used by any new applications. Applications should consider porting away from these interfaces since they may be removed in future versions.

Affected products

• GNU C Library (glibc): from 2.2

References

• https://inbox.sourceware.org/libc-announce/7a655d55-276f-41fe-b550-feb3ebb2ce91@redhat.com/T/#u
• https://sourceware.org/bugzilla/show_bug.cgi?id=34069
• https://cert-portal.siemens.com/productcert/html/ssa-082556.html

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