Memory Allocation with Excessive Size Value Affecting dulwich package, versions [,1.2.5)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-DULWICH-17266106
- published9 Jun 2026
- disclosed8 Jun 2026
- creditLiyi, Ziyue, Strick, Maurice, Chenchen
Introduced: 8 Jun 2026
CVE-2026-47734 (opens in a new tab)How to fix?
Upgrade dulwich to version 1.2.5 or higher.
Overview
Affected versions of this package are vulnerable to Memory Allocation with Excessive Size Value through the ReceivePackHandler via add_thin_pack/apply_delta flows when handling crafted thin packs with attacker-controlled delta headers. An attacker can cause excessive memory allocation by pushing a specially crafted thin pack that declares a large destination size, leading to resource exhaustion and potential denial of service. This is only exploitable if the server exposes git-receive-pack functionality and accepts pushes from untrusted or authenticated clients.
Workaround
This vulnerability can be mitigated by restricting push access to trusted, authenticated clients only, disabling push functionality if not needed, or running the server under an OS-level memory limit (such as ulimit, cgroups/MemoryMax, or a container memory limit) to prevent host exhaustion.