CVE-2026-31961 Unbounded memory allocation in Quill via unvalidated size fields in Mach-O binary parsing
An attacker can cause denial of service by supplying a crafted Mach-O binary that triggers unbounded memory allocation in Quill.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-31961?
CVE-2026-31961 is a medium-severity denial of service vulnerability in anchore quill, published on 11 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Quill provides simple mac binary signing and notarization from any platform. Quill before version v0.7.1 contains an unbounded memory allocation vulnerability when parsing Mach-O binaries. Exploitation requires that Quill processes an attacker-supplied Mach-O binary, which is most likely in environments such as CI/CD pipelines, shared signing services, or any workflow where externally-submitted binaries are accepted for signing. When parsing a Mach-O binary, Quill reads several size and count fields from the LC_CODE_SIGNATURE load command and embedded code signing structures (SuperBlob, BlobIndex) and uses them to allocate memory buffers without validating that the values are reasonable or consistent with the actual file size. Affected fields include DataSize, DataOffset, and Size from the load command, Count from the SuperBlob header, and Length from individual blob headers. An attacker can craft a minimal (~4KB) malicious Mach-O binary with extremely large values in these fields, causing Quill to attempt to allocate excessive memory. This leads to memory exhaustion and denial of service, potentially crashing the host process. Both the Quill CLI and Go library are affected when used to parse untrusted Mach-O files. This vulnerability is fixed in 0.7.1.
Weakness: CWE-770
Which versions are affected by CVE-2026-31961?
3 open source packages ship an affected version, including github.com/anchore/quill. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/anchore/quill Go | All versions | 0.7.1 |
github.com/anchore/quill Go | All versions | 0.7.1 |
github.com/anchore/quill Go | All versions | 0.7.1 |
Products include Anchore Quill.
How do I fix CVE-2026-31961?
Upgrade github.com/anchore/quill to 0.7.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-31961 being exploited?
There is no known exploitation of CVE-2026-31961 in the wild and no public exploit code.
Other vulnerabilities in anchore quill
Sources
Also known as GHSA-xj69-m9qq-8m94, GO-2026-4675.