CVE-2026-28525
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.
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
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
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 |
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.
In short
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.
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