CVE-2026-27626: OliveTin: OS Command Injection via `password` argument type and webhook JSON extraction bypasses shell safety checks

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. 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 0.7%, percentile 51: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 51% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes github.com/OliveTin/OliveTin (Go) < 0.0.0-20260222101908-4bbd2eab1532, fixed in 0.0.0-20260222101908-4bbd2eab1532. Check your lockfile, including transitive dependencies.

What it is

OliveTin gives access to predefined shell commands from a web interface. In versions up to and including 3000.10.0, OliveTin's shell mode safety check (checkShellArgumentSafety) blocks several dangerous argument types but not password. A user supplying a password-typed argument can inject shell metacharacters that execute arbitrary OS commands. A second independent vector allows unauthenticated RCE via webhook-extracted JSON values that skip type safety checks entirely before reaching sh -c. When exploiting vector 1, any authenticated user (registration enabled by default, authType: none by default) can execute arbitrary OS commands on the OliveTin host with the permissions of the OliveTin process. When exploiting vector 2, an unauthenticated attacker can achieve the same if the instance receives webhooks from external sources, which is a primary OliveTin use case. When an attacker exploits both vectors, this results in unauthenticated RCE on any OliveTin instance using Shell mode with webhook-triggered actions. As of time of publication, a patched version is not available.

From the GitHub advisory

Summary

OliveTin's shell mode safety check (checkShellArgumentSafety) blocks several dangerous argument types but not password. A user supplying a password-typed argument can inject shell metacharacters that execute arbitrary OS commands. A second independent vector allows unauthenticated RCE via webhook-extracted JSON values that skip type safety checks entirely before reaching sh -c.

Details

Vector 1 — password type bypasses shell safety check (PR:L)

service/internal/executor/arguments.go has two gaps:

Weakness type: CWE-78.

Product: github.com/OliveTin/OliveTin (Go) · Assigned by: GitHub_M · Published: 2026-02-25

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• 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 no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.67% probability of exploitation activity in the next 30 days; percentile 51.

Timeline

• 2026-02-25 — CVE record published by GitHub_M
• 2026-02-25 — GitHub-reviewed advisory GHSA-49gm-hh7w-wfvf published (critical)
• 2026-02-27 — 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

1. GitHub Advisory GHSA-49gm-hh7w-wfvf github.com
2. CVE.org record CVE-2026-27626 cve.org
3. NVD entry CVE-2026-27626 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. pkg.go.dev pkg.go.dev

Critical Go advisories · Today’s Security Digest