PatchSiren cyber security CVE debrief
CVE-2020-37239 Exploit Db CVE debrief
CVE-2020-37239 is a critical memory-safety issue in libbabl 0.1.62. A broken double-free detection check can be bypassed when allocator metadata overwrites babl's signature field after a free, allowing babl_free() to be called twice on the same pointer without triggering detection. The result is a plausible path to memory corruption and, in the worst case, code execution.
- Vendor
- Exploit Db
- Product
- Unknown
- CVSS
- CRITICAL 9.3
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-16
- Original CVE updated
- 2026-05-16
- Advisory published
- 2026-05-16
- Advisory updated
- 2026-05-16
Who should care
Security teams, developers, and operators who ship or embed libbabl through image-processing or graphics stacks should prioritize this issue, especially where the affected library version may be present in production builds, packaged dependencies, or containers.
Technical summary
The supplied description and NVD metadata indicate CWE-415 (double free). libbabl's protection logic stores a signature in freed chunks, but libc malloc metadata can overwrite that field during free(). If the signature check is no longer reliable, a second babl_free() on the same pointer may not be detected. That undermines memory-safety enforcement and can lead to heap corruption.
Defensive priority
Critical. Treat as an urgent dependency review and patching item for any environment that may include the affected libbabl release.
Recommended defensive actions
- Inventory where libbabl is used, including transitive dependencies in desktop apps, build systems, containers, and embedded image-processing pipelines.
- Verify the deployed libbabl version against upstream guidance from the babl/GEGL project pages and upgrade to a fixed release if one is available.
- Rebuild downstream packages and container images after updating the dependency so the patched library is actually shipped.
- Prioritize internet-facing or high-value workloads that process untrusted images or user-supplied content, since memory corruption in a parser/library can have broad impact.
- If immediate patching is not possible, isolate affected workloads and increase monitoring for crashes or allocator-related faults until remediation is complete.
Evidence notes
This debrief is based on the supplied CVE description, NVD metadata, and NVD-listed references. NVD lists CWE-415 and references Exploit-DB, GEGL/babl pages, and a VulnCheck advisory. No KEV entry was supplied in the provided corpus.
Official resources
Publicly recorded by CVE/NVD on 2026-05-16 per the supplied CVE timeline. The NVD metadata points to external references including Exploit-DB, GEGL/babl pages, and a VulnCheck advisory.