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Memory LeakWeakness · CWE-401

CVE-2026-1757

MEDIUM · 6.2 CVSS v3.1 Published 2026-02-02
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
No privileges Zero-click

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 identified in the interactive shell of the xmllint utility, part of the libxml2 project, where memory allocated for user input is not properly released under certain conditions. When a user submits input consisting only of whitespace, the program skips command execution but fails to free the allocated buffer. Repeating this action causes memory to continuously accumulate. Over time, this can exhaust system memory and terminate the xmllint process, creating a denial-of-service condition on the local system.

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 · high confidence

A memory leak exists in xmllint's interactive shell where whitespace-only input causes allocated buffers to not be freed. The program correctly skips command execution for whitespace but fails to release the memory, causing cumulative memory exhaustion with repeated whitespace input leading to local DoS.

MitigationUpdate libxml2 to the version containing the fix for this memory leak. If a patch is unavailable, limit or monitor xmllint interactive shell usage to prevent memory exhaustion attacks.

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
Local
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

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. Check if xmllint is installed
    Run 'which xmllint' or 'xmllint --version' to verify the binary exists on the system
    Affected if xmllint binary is present on the system
  2. Determine the installed xmllint/libxml2 version
    Run 'xmllint --version' and note the libxml2 version number displayed
    Affected if The installed version is older than the fixed version containing the CVE-2026-1757 patch
  3. Verify interactive shell access
    Run 'xmllint' without arguments or with '--shell' to confirm the interactive shell mode is available
    Affected if Users can access xmllint interactive shell mode
  4. Check system usage context
    Identify if xmllint is used in scripts, automation, or by users who might provide repeated whitespace input
    Affected if xmllint interactive shell is accessible to untrusted input or automated processes that could repeatedly send whitespace

A system is affected if it runs a version of xmllint/libxml2 prior to the fix for CVE-2026-1757 and provides access to the interactive shell where repeated whitespace input can be provided.

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 libxml2 to the version containing the fix for this memory leak. If a patch is unavailable, limit or monitor xmllint interactive shell usage to prevent memory exhaustion attacks.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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Scan for this in your stack

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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-2026-1757 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
  • No weaponised exploit code, or anything meant to cause harm
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