CVE-2026-28525
SWUpdate Integer Underflow in Multipart Upload Parser
CVE-2026-28525 is a high vulnerability (CVSS 8.2) in Sbabic Swupdate, published April 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.32%, the 24th percentile. Fixed in swupdate 2022.12+dfsg-4+deb12u2.
- Severity
- 8.2 HighCVSS 4.0, CVE List
- Exploit chance
- 0.32%EPSS, 24th percentile
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
2022.12+dfsg-4+deb12u2swupdate +7 more
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
swupdateDebian:12 | before 2022.12+dfsg-4+deb12u2, plus listed versions 2022.12+dfsg-42022.12+dfsg-4+deb12u12022.12+dfsg-4+deb12u1~bpo11+1 | 2022.12+dfsg-4+deb12u2 |
swupdateDebian:13 | before 2024.12.1+dfsg-3+deb13u2, plus listed versions 2024.12.1+dfsg-32024.12.1+dfsg-3+deb13u1 | 2024.12.1+dfsg-3+deb13u2 |
swupdateDebian:14 | before 2025.12+dfsg-9, plus listed versions 2024.12.1+dfsg-32025.05+dfsg-12025.05+dfsg-22025.05+dfsg-2~bpo13+12025.05+dfsg-3 Show 11 moreShow less2025.05+dfsg-3~bpo13+12025.12+dfsg-12025.12+dfsg-22025.12+dfsg-2~bpo13+12025.12+dfsg-32025.12+dfsg-42025.12+dfsg-52025.12+dfsg-62025.12+dfsg-72025.12+dfsg-7~bpo13+12025.12+dfsg-8 | 2025.12+dfsg-9 |
swupdateUbuntu:22.04:LTS | All versions, plus listed versions 2020.11-22021.04-1.12021.04-22021.04-2build12021.11-1 | None known |
swupdateUbuntu:24.04:LTS | All versions, plus listed versions 2023.05+dfsg-32023.05+dfsg-42023.05+dfsg-4build12023.05+dfsg-52023.12+dfsg-12023.12.1+dfsg-1ubuntu12023.12.1+dfsg-1ubuntu42023.12.1+dfsg-1ubuntu5 | None known |
swupdateUbuntu:25.10 | All versions, plus listed versions 2024.12.1+dfsg-1build22024.12.1+dfsg-22024.12.1+dfsg-32025.05+dfsg-2ubuntu1 | None known |
swupdateUbuntu:26.10 | All versions, plus listed versions 2025.12+dfsg-4ubuntu12026.05+dfsg-3ubuntu22026.05+dfsg-4ubuntu12026.05.1+dfsg-1ubuntu12026.05.1+git20261001+dfsg-1ubuntu1 | None known |
swupdateUbuntu:26.04:LTS | All versions, plus listed versions 2025.05+dfsg-2ubuntu12025.05+dfsg-3ubuntu12025.12+dfsg-1ubuntu12025.12+dfsg-2ubuntu12025.12+dfsg-3ubuntu12025.12+dfsg-4ubuntu1 | None known |
What each source reports
CVE List Score used 8.2
SWUpdate Integer Underflow in Multipart Upload Parser
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.
- Record
CVE-2026-28525- CVSS 4.0
- 8.2 High
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 - CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-191, CWE-125
- Updated
- 2026-11-02
EUVDEUVD-2026-25307 8.2
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.
- Record
EUVD-2026-25307- CVSS 4.0
- 8.2 High
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-hggv-rg65-qf4h 8.2
SWUpdate contains an integer underflow vulnerability in the multipart upload parser in...
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 that writes data beyond the allocated receive buffer to a local IPC socket.
- Record
GHSA-hggv-rg65-qf4h- CVSS 4.0
- 8.2 High
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 - CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
NVD 8.2
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.
- Record
CVE-2026-28525- CVSS 4.0
- 8.2 High
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 - CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-125, CWE-191
- Updated
- 2026-11-02
OSV 8.2
SWUpdate Integer Underflow in Multipart Upload Parser
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.
- Record
CVE-2026-28525- CVSS 4.0
- 8.2 High
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 - Weakness
- CWE-125, CWE-191
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-28525 8.2
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.
- Record
DEBIAN-CVE-2026-28525- CVSS 4.0
- 8.2 High
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 - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-28525 8.2
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.
- Record
UBUNTU-CVE-2026-28525- CVSS 4.0
- 8.2 High
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 - CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H - Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
References
github.com/sbabic/swupdate/commit/beee2dc0feef1cfe84f1aa6fc980e104b2e47a74
vulncheck.com/advisories/swupdate-integer-underflow-in-multipart-upload-parser
nvd.nist.gov/vuln/detail/CVE-2026-28525
github.com/advisories/GHSA-hggv-rg65-qf4h
github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28525.json
github.com/sbabic/swupdate
security-tracker.debian.org/tracker/CVE-2026-28525
ubuntu.com/security/CVE-2026-28525
cve.org/CVERecord?id=CVE-2026-28525