CVE-2026-30922
Published: March 19, 2026Last modified: March 28, 2026
Description
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.3, the `pyasn1` library is vulnerable to a Denial of Service (DoS) attack caused by uncontrolled recursion when decoding ASN.1 data with deeply nested structures. An attacker can supply a crafted payload containing thousands of nested `SEQUENCE` (`0x30`) or `SET` (`0x31`) tags with "Indefinite Length" (`0x80`) markers. This forces the decoder to recursively call itself until the Python interpreter crashes with a `RecursionError` or consumes all available memory (OOM), crashing the host application. This is a distinct vulnerability from CVE-2026-23490 (which addressed integer overflows in OID decoding). The fix for CVE-2026-23490 (`MAX_OID_ARC_CONTINUATION_OCTETS`) does not mitigate this recursion issue. Version 0.6.3 fixes this specific issue.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | py3-asn1 | Fixed (0.4.8-r5) |
| 25 LTS | py3-asn1 | Fixed (0.6.3-r0) | |
| Stream | py3-asn1 | Fixed (0.6.3-r0) |
References
- http://www.openwall.com/lists/oss-security/2026/03/20/4
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/errata/RHSA-2026:12176
- https://access.redhat.com/errata/RHSA-2026:13508
- https://access.redhat.com/errata/RHSA-2026:13512
- https://access.redhat.com/errata/RHSA-2026:13545
- https://access.redhat.com/errata/RHSA-2026:13553
- https://access.redhat.com/errata/RHSA-2026:13902
- https://access.redhat.com/errata/RHSA-2026:13916
- https://access.redhat.com/errata/RHSA-2026:13917
- https://access.redhat.com/errata/RHSA-2026:14020
- https://access.redhat.com/errata/RHSA-2026:16009
- https://access.redhat.com/errata/RHSA-2026:17083
- https://access.redhat.com/errata/RHSA-2026:17611
- https://access.redhat.com/errata/RHSA-2026:19138
- https://access.redhat.com/errata/RHSA-2026:19355
- https://access.redhat.com/errata/RHSA-2026:19375
- https://access.redhat.com/errata/RHSA-2026:19712
- https://access.redhat.com/errata/RHSA-2026:20588
- https://access.redhat.com/errata/RHSA-2026:22131
- https://access.redhat.com/errata/RHSA-2026:22132
- https://access.redhat.com/errata/RHSA-2026:22133
- https://access.redhat.com/errata/RHSA-2026:22134
- https://access.redhat.com/errata/RHSA-2026:22135
- https://access.redhat.com/errata/RHSA-2026:22969
- https://access.redhat.com/errata/RHSA-2026:22970
- https://access.redhat.com/errata/RHSA-2026:22987
- https://access.redhat.com/errata/RHSA-2026:24761
- https://access.redhat.com/errata/RHSA-2026:24762
- https://access.redhat.com/errata/RHSA-2026:37275
- https://access.redhat.com/errata/RHSA-2026:6309
- https://access.redhat.com/errata/RHSA-2026:6568
- https://access.redhat.com/errata/RHSA-2026:6720
- https://access.redhat.com/errata/RHSA-2026:6912
- https://access.redhat.com/errata/RHSA-2026:6926
- https://access.redhat.com/errata/RHSA-2026:8437
- https://access.redhat.com/security/cve/CVE-2026-30922
- https://bugzilla.redhat.com/show_bug.cgi?id=2448553
- https://github.com/pyasn1/pyasn1/commit/25ad481c19fdb006e20485ef3fc2e5b3eff30ef0
- https://github.com/pyasn1/pyasn1/security/advisories/GHSA-jr27-m4p2-rc6r
- https://lists.debian.org/debian-lts-announce/2026/05/msg00001.html
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-30922.json