CVE-2026-122299
Dulwich before 1.2.20 Commit Parser Tree Header Misinterpretation
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Active
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.6
Dulwich before 1.2.20 Commit Parser Tree Header Misinterpretation
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
- Record
CVE-2026-122299- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-1250, CWE-115
- Updated
- 2026-11-04
EUVDEUVD-2026-117194
8.6
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
- Record
EUVD-2026-117194- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-05
GitHub AdvisoriesGHSA-6jv4-m4h7-2vv8
8.6
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in...
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
- Record
GHSA-6jv4-m4h7-2vv8- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-115
- Updated
- 2026-11-05
NVD
8.6
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
- Record
CVE-2026-122299- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-115, CWE-1250
- Updated
- 2026-11-05
OSV
8.6
Dulwich before 1.2.20 Commit Parser Tree Header Misinterpretation
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
- Record
CVE-2026-122299- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-115, CWE-1250
- Updated
- 2026-11-05
OSVDEBIAN-CVE-2026-122299
8.8
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
- Record
DEBIAN-CVE-2026-122299- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-05
OSVUBUNTU-CVE-2026-122299
8.6
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
- Record
UBUNTU-CVE-2026-122299- CVSS 4.0
- 8.6 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-06
OSVAZL-112720 No score
CVE-2026-122299 affecting package python-dulwich 0.21.7-6
Dulwich before 1.2.20 contains a commit object parsing vulnerability where the read path in _parse_commit resolves a duplicate tree header to the last occurrence instead of the first, diverging from core git's resolution behavior, while Poetry 2.5.1 ships this version and uses dulwich by default for git dependency installation. Attackers can craft a commit object with two tree headers so that reviewers and CI using git see a benign tree while Poetry's dulwich-based checkout resolves to a different attacker-controlled tree containing malicious build scripts such as setup.py, resulting in unreviewed code execution on the install or build host.
- Record
AZL-112720- Updated
- 2026-11-07
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
python-dulwichAzure Linux:3 |
through 0.21.7-6 | None known |
dulwichDebian:12 |
All versions, plus listed versions 0.21.2-10.21.5-10.21.6-10.22.5-10.22.7-1 Show 17 moreShow less0.22.7-20.24.10-10.24.2-10.24.2-21.0.0-11.0.0-21.1.0-11.1.0-21.1.0-31.2.0-11.2.1-11.2.11-11.2.12-11.2.17-11.2.5-11.2.7-11.2.7-2 |
None known |
dulwichDebian:13 |
All versions, plus listed versions 0.22.7-10.22.7-20.24.10-10.24.2-10.24.2-2 Show 13 moreShow less1.0.0-11.0.0-21.1.0-11.1.0-21.1.0-31.2.0-11.2.1-11.2.11-11.2.12-11.2.17-11.2.5-11.2.7-11.2.7-2 |
None known |
dulwichDebian:14 |
All versions, plus listed versions 0.22.7-10.22.7-20.24.10-10.24.2-10.24.2-2 Show 13 moreShow less1.0.0-11.0.0-21.1.0-11.1.0-21.1.0-31.2.0-11.2.1-11.2.11-11.2.12-11.2.17-11.2.5-11.2.7-11.2.7-2 |
None known |
dulwichUbuntu:16.04:LTS |
All versions, plus listed versions 0.11.2-1ubuntu10.12.0-10.12.0-1build10.12.0-1build2 |
None known |
dulwichUbuntu:18.04:LTS |
All versions, plus listed versions 0.18.2-1build10.18.5-1 |
None known |
dulwichUbuntu:20.04:LTS |
All versions, plus listed versions 0.19.11-20.19.14-4ubuntu10.19.15-10.19.15-1build1 |
None known |
dulwichUbuntu:22.04:LTS |
All versions, plus listed versions 0.20.15-1ubuntu10.20.31-1ubuntu10.20.31-1.10.20.31-1.1build1 |
None known |
dulwichUbuntu:24.04:LTS |
All versions, plus listed versions 0.21.6-10.21.6-1build10.21.6-1build2 |
None known |
dulwichUbuntu:26.10 |
All versions, plus listed versions 1.1.0-31.2.12-1 |
None known |
dulwichUbuntu:26.04:LTS |
All versions, plus listed versions 0.22.7-10.24.2-21.1.0-2ubuntu11.1.0-3 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases, references | OSV | |
| affected, aliases, references | OSV | |
| affected, aliases, references | OSV | |
| references | OSV | |
| published | EUVD, NVD | |
| aliases, published | EUVD | |
| aliases, references | GitHub Advisories | |
| first indexed | CVE List |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-122299 is a high vulnerability (CVSS 8.6) in Jelmer Dulwich, published November 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.33%, the 25th percentile. No source names a fixed version.
References
github.com/jelmer/dulwich/releases/tag/dulwich-1.2.20
github.com/jelmer/dulwich/commit/b77f385b4b0d2d2c7f5ac39dae628948f7ad3a96
vulncheck.com/advisories/dulwich-before-commit-parser-tree-header-misinterpretation
nvd.nist.gov/vuln/detail/CVE-2026-122299
github.com/advisories/GHSA-6jv4-m4h7-2vv8
github.com/CVEProject/cvelistV5/tree/main/cves/2026/122xxx/CVE-2026-122299.json