CVE-2026-47734
published 2026-06-10CVE-2026-47734: 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…
PriorityP430medium5.7CVSS 3.1
AVNACLPRLUIRSUCNINAH
EPSS
0.19%
8.6th percentile
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 dest_size. When dulwich ingested it via add_thin_pack / apply_delta, 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. add_thin_pack now accepts a max_input_size 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.
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| ansible-automation-platform-26 | controller-rhel9 | — | — |
| ansible-automation-platform-26 | eda-controller-rhel9 | — | — |
| ansible-automation-platform-26 | lightspeed-chatbot-rhel9 | — | — |
| ansible-automation-platform-27 | controller-rhel9 | — | — |
| ansible-automation-platform-27 | eda-controller-rhel9 | — | — |
| dulwich_project | dulwich | >= 0.1.0 < 1.2.5 | 1.2.5 |
| jelmer | dulwich | — | — |
| rhoai | odh-kserve-agent-rhel9 | — | — |
| rhoai | odh-kserve-autogluon-server-rhel9 | — | — |
| rhoai | odh-kserve-controller-rhel9 | — | — |
| rhoai | odh-kserve-router-rhel9 | — | — |
| rhoai | odh-kserve-storage-initializer-rhel9 | — | — |
CVSS provenance
nvdv3.15.7MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
vendor_redhat5.7MEDIUM
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GHSA
Dulwich has unbounded memory allocation in receive-pack from crafted thin packs
ghsa·2026-06-08
CVE-2026-47734 [MEDIUM] CWE-400 Dulwich has unbounded memory allocation in receive-pack from crafted thin packs
Dulwich has unbounded memory allocation in receive-pack from crafted thin packs
## 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 dest_size. When dulwich ingested it via add_thin_pack / apply_delta, 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.
add_thin_pack now accepts
Red Hat
dulwich: Dulwich: Denial of Service via crafted Git thin pack
vendor_redhat·2026-06-10·CVSS 5.7
CVE-2026-47734 [MEDIUM] CWE-1285 dulwich: Dulwich: Denial of Service via crafted Git thin pack
dulwich: Dulwich: Denial of Service via crafted Git thin pack
A flaw was found in Dulwich, a pure-Python implementation of Git file formats and protocols. A remote attacker with push access to a Dulwich-based Git server could send a specially crafted thin pack. This crafted pack, with a manipulated delta header, would cause the server to allocate excessive amounts of memory, leading to a Denial of Service (DoS) condition. This vulnerability allows an authenticated attacker to disrupt the availability of the Git server.
Statement: This Moderate impact denial of service flaw in Dulwich affects Red Hat products utilizing Dulwich-based Git server functionalities. An authenticated attacker with push access could send a crafted Git thin pack, causing excessive memory allocation and disrupting
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-47734 python-dulwich: Dulwich: Denial of Service via crafted Git thin pack [fedora-all]
bugzilla·2026-06-11·CVSS 5.7
CVE-2026-47734 [MEDIUM] CVE-2026-47734 python-dulwich: Dulwich: Denial of Service via crafted Git thin pack [fedora-all]
CVE-2026-47734 python-dulwich: Dulwich: Denial of Service via crafted Git thin pack [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-47734 python-dulwich: Dulwich: Denial of Service via crafted Git thin pack [epel-all]
bugzilla·2026-06-11·CVSS 5.7
CVE-2026-47734 [MEDIUM] CVE-2026-47734 python-dulwich: Dulwich: Denial of Service via crafted Git thin pack [epel-all]
CVE-2026-47734 python-dulwich: Dulwich: Denial of Service via crafted Git thin pack [epel-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-47734 dulwich: Dulwich: Denial of Service via crafted Git thin pack
bugzilla·2026-06-10·CVSS 5.7
CVE-2026-47734 [MEDIUM] CVE-2026-47734 dulwich: Dulwich: Denial of Service via crafted Git thin pack
CVE-2026-47734 dulwich: Dulwich: Denial of Service via crafted Git thin pack
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 dest_size. When dulwich ingested it via add_thin_pack / apply_delta, 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. add_thin_pack now acc
2026-06-10
Published