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VulnerabilityPublished

CVE-2026-77117: The GNU C Library glibc · Infinite Loop

Affects The GNU C Library glibcSource CVE Database V5

0

Mentioned vulnerabilities

Not known to be exploited · CVSS 5.9 Medium.

Data as of 26 Oct 2026, 12:30 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 29% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-09-15.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
The GNU C LibraryglibcAffected
  • >=2.3 <=2.44
Fixed in–

AI-suggested

Until a fix is available, avoid processing untrusted SHIFT_JISX0213 input with glibc versions 2.3 through 2.44 or ensure output buffers are sufficiently large to prevent splitting code points during conversion.

Description

CVE-2026-77117 is a vulnerability in the GNU C Library (glibc) versions 2.3 through 2.44 involving an infinite loop during conversion of crafted SHIFT_JISX0213 input to UCS-4 or the internal wide character encoding. The issue arises when a SHIFT_JISX0213 sequence decodes to two code points but the output buffer only has room for the first, causing the converter to repeatedly emit a pending character without consuming further input, leading to application hang. This affects only the SHIFT_JISX0213 character set, which is uncommon.

References

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