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Out-of-bounds WriteWeakness · CWE-787

CVE-2026-1489

MEDIUM · 5.4 CVSS v3.1 Published 2026-01-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
61/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A flaw was found in GLib. An integer overflow vulnerability in its Unicode case conversion implementation can lead to memory corruption. By processing specially crafted and extremely large Unicode strings, an attacker could trigger an undersized memory allocation, resulting in out-of-bounds writes. This could cause applications utilizing GLib for string conversion to crash or become unstable.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

GLib contains an integer overflow vulnerability in its Unicode case conversion implementation where processing extremely large Unicode strings causes an undersized memory allocation, leading to out-of-bounds memory writes and potential memory corruption.

MitigationUpdate GLib to a patched version that includes proper integer overflow checks in the Unicode case conversion allocation logic.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify GLib library is present
    Run 'pkg-config --modversion glib-2.0' or check for libglib-2.0.so in /usr/lib/
    Affected if GLib is not installed or the library file is missing
  2. Determine installed GLib version
    Use 'pkg-config --modversion glib-2.0' or inspect the version header at /usr/include/glib-2.0/glib/version.h
    Affected if The version cannot be determined or is older than any patched release containing overflow checks
  3. Identify use of Unicode case conversion functions
    Search source code or binaries for calls to g_utf8_strup, g_utf8_strdown, g_utf8_strcaseup, g_utf8_strcasedown, or g_unichar_toupper/tolower with string input
    Affected if The vulnerable Unicode case conversion functions are actively used in deployed code
  4. Check for processing of large Unicode strings
    Review application logic to determine if it processes Unicode strings that could approach or exceed reasonable length limits (megabytes or larger)
    Affected if Applications process externally-sourced Unicode strings without length validation before case conversion

A system is affected if it runs a GLib version lacking integer overflow checks in Unicode case conversion AND actively processes large Unicode strings through the vulnerable functions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update GLib to a patched version that includes proper integer overflow checks in the Unicode case conversion allocation logic.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-1489 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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