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No exploitation reportedFix available

CVE-2026-28525

No exploitation reported by the sources we read.

  • Published2026-04-23
  • WeaknessCWE-125 · CWE-191

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

SWUpdate contains an integer underflow vulnerability in the multipart upload parser in mongoose_multipart.c that allows unauthenticated attackers to cause a denial of service by sending a crafted HTTP POST request to /upload with a malformed multipart boundary and controlled TCP stream timing. Attackers can trigger an integer underflow in the mg_http_multipart_continue_wait_for_chunk() function when the buffer length falls within a specific range, causing an out-of-bounds heap read past the allocated receive buffer to a local IPC socket.

Timeline

dates in UTC
  1. 2026-04-2321:16CVE publishedNVD

Versions per branch

NVD
Swupdate
BranchAffectedFixed in
2025.12≤ 2025.12no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As VulnCheck, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • sbabic swupdateother versions: not affected

    https://github.com/sbabic/swupdate

    Affected
    • ≤ 2025.12no fix statedcustom

    Not affected = beee2dc0feef1cfe84f1aa6fc980e104b2e47a74

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-07-28

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • swupdateUbuntu:26.10all versions · no fixed version listed
  • swupdateUbuntu:26.04:LTSall versions · no fixed version listed
  • swupdateUbuntu:25.10all versions · no fixed version listed
  • swupdateUbuntu:24.04:LTSall versions · no fixed version listed
  • swupdateUbuntu:22.04:LTSall versions · no fixed version listed
  • swupdateDebian:14all versions · fixed in 2025.12+dfsg-9
  • swupdateDebian:13all versions · fixed in 2024.12.1+dfsg-3+deb13u2
  • swupdateDebian:12all versions · fixed in 2022.12+dfsg-4+deb12u2

Full record on NVD

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVE recordread 2026-10-27
  • CISA-ADPSSVC decisionnone2026-04-25
  • CNACVSS 4.08.2known since 2026-10-27
  • CNACVSS 3.16.8known since 2026-10-27
  • CNAweakness (CWE)CWE-125, CWE-191known since 2026-10-27
  • FIRST EPSSEPSS score0.3 %2026-11-08
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS 4.0 vector
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-04-23
Last Modified
2026-10-26
NVD status
Analyzed
GitHub Advisory
GHSA-hggv-rg65-qf4h

Frequently asked questions

What is CVE-2026-28525?

SWUpdate contains an integer underflow vulnerability in the multipart upload parser in mongoose_multipart.c that allows unauthenticated attackers to cause a denial of service by sending a crafted HTTP POST request to /upload with a malformed multipart boundary and controlled TCP stream timing. Attackers can trigger an integer underflow in the mg_http_multipart_continue_wait_for_chunk() function when the buffer length falls within a specific range, causing an out-of-bounds heap read past the allocated receive buffer to a local IPC socket.

Is CVE-2026-28525 actively exploited?

Active exploitation of CVE-2026-28525 has not been confirmed. Its EPSS score was 0.3% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-28525?

CVE-2026-28525 has a CVSS v3 base score of 6.8 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H.

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