dbcve.org
LibmicrohttpdWeb server / proxy · Gnu

CVE-2025-62689

HIGH · 7.5 CVSS v3.0 Published 2025-11-10
Fix available
A fix is available. Upgrade to 2025-09-16 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click Patch available

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
NULL pointer dereference vulnerability exists in GNU libmicrohttpd v1.0.2 and earlier. The vulnerability was fixed in commit ff13abc on the master branch of the libmicrohttpd Git repository, after the v1.0.2 tag. A specially crafted packet sent by an attacker could cause a denial-of-service (DoS) condition.

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
How this class of weakness works · CWE-122

Data overflows a buffer allocated on the heap, corrupting neighbouring heap structures and allocator metadata that a patient attacker can groom into control of execution. It is subtler than a stack overflow but just as dangerous. The fix is validating lengths before every write and using safe allocators and bounded operations.

General guidance for the heap-based buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
LibmicrohttpdWeb server / proxy
Affected:< 2025-09-16

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
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

dbcve · scoped
Upgrade available Upgrade to 2025-09-16 or later
Fixed in 2025-09-16
Vendor patch git.gnunet.org →
Recommended fix Moderate confidence

libmicrohttpd version newer than 2025-09-16 (or master branch after commit ff13abc)

  1. Check current libmicrohttpd version installed (e.g., via dpkg -l libmicrohttpd, rpm -q libmicrohttpd, or MHD_get_version())
  2. Download the latest libmicrohttpd source from https://www.gnu.org/software/libmicrohttpd/ or clone the git repository: git clone https://git.gnunet.org/libmicrohttpd.git
  3. If using the git repository, verify the fix is present by checking commit ff13abc1c1d7d2b30d69d5c0bd4a237e1801c50b: git log --oneline | grep ff13abc or git show ff13abc
  4. Rebuild and reinstall libmicrohttpd from source using standard build steps: ./configure && make && make install
  5. Restart any services or applications that use libmicrohttpd to load the updated library
  6. Verify the new version is loaded and the vulnerability is addressed

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

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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-2025-62689 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
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  • Version or environment caveats, and links to real fixes
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