CVE-2026-81027

HIGH
Published Aug 26, 2026 Modified Aug 26, 2026 CWE-862

Description

one-api gates one of its two channel-pinning paths and not the other. middleware/auth.go permits a request to name a specific channel either through a suffix on the API key or through a URL path parameter. The suffix path is reached only after model.IsAdmin succeeds and otherwise rejects the caller, while the path-parameter branch sets the selected-channel value from c.Param("channelid") with no role check at all. The route carrying that parameter sits behind token authentication only, so any account holding a valid API token reaches it. The value flows to the distributor, which loads the channel by integer identifier with no scoping to the caller's user or group, and then sets the outbound Authorization header to that channel's stored key and directs the request at the channel's base URL. A low-privilege account can therefore pin any channel by incrementing an identifier, causing the server to make upstream requests bearing an operator-configured provider key the account was never granted, and bypassing both the per-group restriction and the channel's model allowlist.

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CVSS v3.1 Score

8.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0029
Probability of exploitation
0.21%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Frequently Asked Questions

What is CVE-2026-81027? +
one-api gates one of its two channel-pinning paths and not the other. middleware/auth.go permits a request to name a specific channel either through a suffix on the API key or through a URL path parameter. The suffix path is reached only after model.IsAdmin succeeds and otherwise rejects the caller, while the path-parameter branch sets the selected-channel value from c.Param("channelid") with no role check at all. The route carrying that parameter sits behind token authentication only, so any account holding a valid API token reaches it. The value flows to the distributor, which loads the channel by integer identifier with no scoping to the caller's user or group, and then sets the outbound Authorization header to that channel's stored key and directs the request at the channel's base URL. A low-privilege account can therefore pin any channel by incrementing an identifier, causing the server to make upstream requests bearing an operator-configured provider key the account was never granted, and bypassing both the per-group restriction and the channel's model allowlist. It has a CVSS v3.1 base score of 8.5 (HIGH).
How severe is CVE-2026-81027? +
CVE-2026-81027 has a CVSS v3.1 score of 8.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0029, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-81027? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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