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Echo: dulwich: security update to 1.2.5

medium Tenable Cloud Security Plugin ID 460970

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - 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. (CVE-2026-47734)

Solution

Update the dulwich library and its related packages to version 1.2.5 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-47734

Plugin Details

Severity: Medium

ID: 460970

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/3/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.77

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2026-47734

CVSS v3

Risk Factor: Medium

Base Score: 5.7

Temporal Score: 5

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 7/1/2026

Vulnerability Publication Date: 6/8/2026

Reference Information

CVE: CVE-2026-47734