CVE-2026-47734 is a medium-severity uncontrolled resource consumption vulnerability in dulwich (pip), affecting versions >= 0.1.0, < 1.2.5. It is fixed in 1.2.5.
Impact An uncontrolled-resource-consumption (memory exhaustion) denial-of-service vulnerability (CWE-400 / CWE-789). A client with push access could push a tiny crafted thin pack (~174 bytes) whose delta header declares a huge destsize. When dulwich ingested it via addthinpack / applydelta, it would allocate hundreds of MB of memory based on that attacker-controlled size, with no relationship to the actual bytes received. Who is impacted: Operators running a Dulwich-based Git server that exposes git-receive-pack (i.e. accepts pushes) - for example via dulwich.server functionality, the HTTP smart server, or anything built on ReceivePackHandler. Patches Patched in 1.2.5. addthinpack now accepts a maxinputsize keyword (bytes; 0/None = unlimited, matching git's semantics), and ReceivePackHandler reads receive.maxInputSize from the repository config and passes it through. Wire reads are counted and a PackInputTooLarge exception is raised once the cap is exceeded - equivalent to git index-pack --max-input-size. Users should upgrade to Dulwich 1.2.5 or later and set receive.maxInputSize in their server's repository config to a sane bound for their environment. Workarounds On unpatched versions, receive.maxInputSize has no effect, so it cannot be used as a workaround. Until upgrading, operators should: Restrict dulwich-receive-pack (push) access to trusted, authenticated clients only, or disable it entirely on servers that only need to serve fetches. Run the server under an OS-level memory limit (e.g. ulimit, cgroups/MemoryMax, or a container memory limit) so a malicious push is killed rather than taking down the host. Resources git's receive.maxInputSize / git index-pack --max-input-size documentation Reported by Liyi, Ziyue, Strick, Maurice and Chenchen @ University of Sydney
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
CVE-2026-47734 has a CVSS score of 5.7 (Medium). The vector is network-reachable, low privileges required, and user interaction required. 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 (1.2.5). Upgrading removes the vulnerable code path.
pip
dulwich (>= 0.1.0, < 1.2.5)dulwich → 1.2.5 (pip)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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CVE-2026-47734 is a medium-severity uncontrolled resource consumption vulnerability in dulwich (pip), affecting versions >= 0.1.0, < 1.2.5. It is fixed in 1.2.5. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
CVE-2026-47734 has a CVSS score of 5.7 (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.
dulwich (pip) versions >= 0.1.0, < 1.2.5 is affected.
Yes. CVE-2026-47734 is fixed in 1.2.5. Upgrade to this version or later.
Whether CVE-2026-47734 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
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.
Upgrade dulwich to 1.2.5 or later.