Description
cbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) (RFC 8949) serialization format. Starting in version 5.5.1 and prior to version 5.6.2, an attacker can crash a service using cbor2 to parse a CBOR binary by sending a long enough object. Version 5.6.2 contains a patch for this issue.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| agronholm | cbor2 | >= 5.5.1, < 5.6.2 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | cbor2 | 5.6.2-1 | — |
| Debian 13 | cbor2 | 5.6.2-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | cbor2 | No fix yet | — |
| Ubuntu 26.04 LTS | cbor2 | No fix yet | — |
| Ubuntu 25.10 | cbor2 | No fix yet | — |
| Ubuntu 24.04 LTS | cbor2 | No fix yet | — |
| Ubuntu 22.04 LTS | cbor2 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | python-cbor2 | 5.6.5-160000.3.1 | SUSE-SU-2025:21168-1 |
| SLES 16.0 | python-cbor2 | 5.6.5-160000.3.1 | SUSE-SU-2025:21168-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-cbor2 | 5.6.5-2.1 | openSUSE-SU-2025:14733-1 |
| openSUSE Leap 16.0 | python-cbor2 | 5.6.5-160000.3.1 | openSUSE-SU-2025:20133-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | cbor2 | >= 5.5.1, < 5.6.2 | 5.6.2 | GHSA-375g-39jq-vq7m |
Advisories 3
- openSUSE-SU-2025:20133-1 Security update for python-cbor2 SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:21168-1 Security update for python-cbor2 SUSE / openSUSE Security Updates · Mar 23, 2026
- openSUSE-SU-2025:14733-1 python311-cbor2-5.6.5-2.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/agronholm/cbor2/security/advisories/GHSA-375g-39jq-vq7m
- https://github.com/agronholm/cbor2/pull/204
- https://github.com/agronholm/cbor2/commit/387755eacf0be35591a478d3c67fe10618a6d542
- https://github.com/agronholm/cbor2/commit/4de6991ba29bf2290d7b9d83525eda7d021873df
- https://github.com/agronholm/cbor2/releases/tag/5.6.2
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GX524ZG2XJWFV37UQKQ4LWIH4UICSGEQ/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BT42VXZMMMCSSHMA65KKPOZCXJEYHNR5/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PWC3VU6YV6EXKCSX5GTKWLBZIDIJNQJY/