CVE-2026-28525
CVE-2026-28525 is a medium-severity vulnerability in Swupdate with a CVSS 3.x base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: Medium (CVSS 3.x base score 6.8)
- CVSS v4: 8.2
- EPSS exploit prediction: 0% (23rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-25307
- Weakness: CWE-125
- Affected product: Swupdate
- Published:
- Last modified:
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.
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.
- How severe is CVE-2026-28525?
- CVE-2026-28525 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-28525 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-28525?
- CVE-2026-28525 affects Swupdate. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-28525?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-28525 have an EU (EUVD) identifier?
- Yes. CVE-2026-28525 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-25307.
- When was CVE-2026-28525 published?
- CVE-2026-28525 was published on 2026-04-23 and last updated on 2026-06-17.
References
- https://github.com/sbabic/swupdate/commit/beee2dc0feef1cfe84f1aa6fc980e104b2e47a74
- https://www.vulncheck.com/advisories/swupdate-integer-underflow-in-multipart-upload-parser
Affected products (1)
- cpe:2.3:a:swupdate:swupdate:*:*:*:*:*:*:*:*
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