CVE-2026-47734
- Source
- https://cve.org/CVERecord?id=CVE-2026-47734
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47734.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-47734
- Aliases
- Downstream
- Published
- 2026-06-10T22:11:02.704Z
- Modified
- 2026-07-08T08:05:19.213877964Z
- Severity
-
- 5.7 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H CVSS Calculator
- Summary
- Dulwich has unbounded memory allocation in receive-pack from crafted thin packs
- Details
-
Dulwich is a pure-Python implementation of the Git file formats and protocols. Starting in version 0.1.0 and prior to version 1.2.5, 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. 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 - are impacted. The issue is 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. 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 and/or 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.
- Database specific
{ "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47734.json", "cwe_ids": [ "CWE-400", "CWE-789" ], "cna_assigner": "GitHub_M" }- References