Security Digest · Vulnerability record
CVE-2026-25921: Gogs: Cross-repository LFS object overwrite via missing content hash verification
Gogs is an open source self-hosted Git service.
CVSS 9.3 Critical EPSS 0.3% · p20
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.3%, percentile 20: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 20% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
gogs.io/gogs(Go) <= 0.14.1, fixed in 0.14.2. Check your lockfile, including transitive dependencies.
What it is
Gogs is an open source self-hosted Git service. Prior to version 0.14.2, overwritable LFS object across different repos leads to supply-chain attack, all LFS objects are vulnerable to be maliciously overwritten by malicious attackers. This issue has been patched in version 0.14.2.
From the GitHub advisory
Summary Overwritable LFS object across different repos leads to supply-chain attack, all LFS objects are vulnerable to be maliciously overwritten by malicious attackers.
Details Gogs store all LFS objects in the same place, no isolation between different repositories. (repo id not concatenated to storage path) https://github.com/gogs/gogs/blob/7a2dffa95ac64f31c8322cb50d32694b05610144/internal/lfsutil/storage.go#L52-L58
Gogs does not verify uploaded LFS file content against its claimed SHA-256, meaning attackers can manipulate the uploaded file like injecting backdoor. https://github.com/gogs/gogs/blob/7a2dffa95ac64f31c8322cb50d32694b05610144/internal/lfsutil/storage.go#L79-L89
Here's the comment that trust client to retry upload allowing them to overwrite. However, this assumption does not hold in the case of a malicious client. https://github.com/gogs/gogs/blob/7a2dffa95ac64f31c8322cb50d32694b05610144/internal/route/lfs/basic.go#L111-L113
PoC
Weakness type: CWE-345.
Product: gogs.io/gogs (Go) · Assigned by: GitHub_M · Published: 2026-03-05
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | gogs.io/gogs | <= 0.14.1 | 0.14.2 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| gogs | gogs | < 0.14.2 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.3 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L |
| GitHub | 3.1 | 9.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 0.29% probability of exploitation activity in the next 30 days; percentile 20.
Timeline
- — CVE record published by GitHub_M
- — GitHub-reviewed advisory GHSA-cj4v-437j-jq4c published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-cj4v-437j-jq4c github.com
- CVE.org record CVE-2026-25921 cve.org
- NVD entry CVE-2026-25921 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com