CVE-2026-31959

Fixed in Quill version v0.7.1

Workarounds

None

Credit

Anchore would like to thank opera-aklajn (Opera) for reporting this vulnerability

Resources

• Apple Get Submission Log API Documentation

Quill before version v0.7.1 contains a Server-Side Request Forgery (SSRF) vulnerability when attempting to fetch the Apple notarization submission logs. Exploitation requires the ability to modify API responses from Apple's notarization service, which is not possible under standard network conditions due to HTTPS with proper TLS certificate validation; however, environments with TLS-intercepting proxies (common in corporate networks), compromised certificate authorities, or other trust boundary violations are at risk.

When retrieving submission logs, Quill fetches a URL provided in the API response without validating that the scheme is https or that the host does not point to a local or multicast IP address. An attacker who can tamper with the response can supply an arbitrary URL, causing the Quill client to issue HTTP or HTTPS requests to attacker-controlled or internal network destinations. This could lead to exfiltration of sensitive data such as cloud provider credentials or internal service responses. Both the Quill CLI and library are affected when used to retrieve notarization submission logs.

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

CVE-2026-31959 has a CVSS score of 5.3 (Medium). The vector is reachable from an adjacent network, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.7.1); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-31959? CVE-2026-31959 is a medium-severity improper input validation vulnerability in github.com/anchore/quill (go), affecting versions < 0.7.1. It is fixed in 0.7.1. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
2. How severe is CVE-2026-31959? CVE-2026-31959 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/anchore/quill are affected by CVE-2026-31959? github.com/anchore/quill (go) versions < 0.7.1 is affected.
4. Is there a fix for CVE-2026-31959? Yes. CVE-2026-31959 is fixed in 0.7.1. Upgrade to this version or later.
5. Is CVE-2026-31959 exploitable, and should I be worried? Whether CVE-2026-31959 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-31959 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-31959? Upgrade github.com/anchore/quill to 0.7.1 or later.