7.5

CVE-2026-30922: pyasn1 Vulnerable to Denial of Service via Unbounded Recursion

Modified
AliasesMGASA-2026-0087SUSE-SU-2026:1075-1SUSE-SU-2026:1076-1
Published 18-03-2026Last modified 17-09-2026

Vulnerability summary

CVE-2026-30922 is a high (CVSS 7.5) Uncontrolled Recursion vulnerability in pyasn1. EPSS estimates a 0.82% chance of exploitation in the next 30 days, higher than 57.1% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Prioritisepublic exploit

Public exploit (GitHub, Date unknown)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.82%
0%100%
Low · -0.11 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 9 · Related 3
RHSA-2026:12176RHSA-2026:13508RHSA-2026:13512RHSA-2026:13916RHSA-2026:17083RHSA-2026:19138

Timeline

  1. 18-03-2026
    PublishedVulnerability first disclosed.
  2. 17-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

8 scores · 8 sources · 2 versions

EPSS trend

Probability

0.82%

Chance of exploitation in the next 30 days

Percentile

57%

Versus all other CVEs

30-day change

Decrease -0.11 pp

From 0.93% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Pyasn1

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Redhat77 products
  • fence-agents< 0:4.10.0-98.el9_7.13 | < 0:4.2.1-112.el8_8.17 | < 0:4.2.1-89.el8_6.22 | < 0:4.2.1-65.el8_4.28 | < 0:4.10.0-62.el9_4.25 | < 0:4.10.0-86.el9_6.17 | < 0:4.10.0-43.el9_2.22
  • fence-agents-aliyun< 0:4.10.0-98.el9_7.13 | < 0:4.2.1-112.el8_8.17 | < 0:4.2.1-89.el8_6.22 | < 0:4.2.1-65.el8_4.28 | < 0:4.10.0-62.el9_4.25 | < 0:4.10.0-86.el9_6.17 | < 0:4.10.0-43.el9_2.22
  • fence-agents-aliyun-debuginfo< 0:4.2.1-112.el8_8.17 | < 0:4.2.1-89.el8_6.22 | < 0:4.2.1-65.el8_4.28
  • fence-agents-all< 0:4.10.0-98.el9_7.13 | < 0:4.2.1-112.el8_8.17 | < 0:4.2.1-89.el8_6.22 | < 0:4.2.1-65.el8_4.28 | < 0:4.10.0-62.el9_4.25 | < 0:4.10.0-86.el9_6.17 | < 0:4.10.0-43.el9_2.22
  • fence-agents-amt-ws< 0:4.10.0-98.el9_7.13 | < 0:4.2.1-112.el8_8.17 | < 0:4.2.1-89.el8_6.22 | < 0:4.2.1-65.el8_4.28 | < 0:4.10.0-62.el9_4.25 | < 0:4.10.0-86.el9_6.17 | < 0:4.10.0-43.el9_2.22
Chainguard55 products
  • airflow-2< 2.11.2-r3
  • airflow-3< 3.1.8-r9
  • ansible-operator< 1.42.2-r0
  • ansible-operator-fips< 1.42.2-r0
  • apache-beam-python-3.12-sdk< 2.71.0-r1
Suse24 products
  • python-pyasn1&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS< 0.4.2-150000.3.16.1 | < 0.5.0-150400.12.13.1
  • python-pyasn1&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS< 0.4.2-150000.3.16.1 | < 0.5.0-150400.12.13.1
  • python-pyasn1&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS< 0.4.2-150000.3.16.1 | < 0.5.0-150400.12.13.1
  • python-pyasn1&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS< 0.4.2-150000.3.16.1 | < 0.5.0-150400.12.13.1
  • python-pyasn1&distro=SUSE Linux Enterprise Micro 5.2< 0.4.2-150000.3.16.1
Wolfi17 products
  • airflow-3< 3.1.8-r9
  • datadog-agent-7.72-core-integrationsAll versions (No fix recorded)
  • datadog-agent-7.73-core-integrations< 7.73.3-r23
  • datadog-agent-7.74-core-integrations< 7.74.1-r24
  • datadog-agent-7.75-core-integrationsAll versions (No fix recorded)
Opensuse3 products
  • python-pyasn1&distro=openSUSE Leap 15.6< 0.5.0-150400.12.13.1
  • python-pyasn1&distro=openSUSE Leap 16.0< 0.6.1-160000.4.1
  • python-pyasn1&distro=openSUSE Tumbleweed< 0.6.3-1.1
Debian1 product
  • pyasn1< 0.4.8-3+deb12u2 | < 0.6.1-1+deb13u2 | < 0.6.3-1
Mageia1 product
  • python-pyasn1< 0.4.8-6.2.mga9
Pyasn11 product
PyPI1 product
  • pyasn1< 0.6.3
Ubuntu1 product
  • pyasn1< 0.1.7-1ubuntu2.1+esm1 | < 0.1.9-1ubuntu0.1~esm1 | < 0.4.2-3ubuntu0.18.04.1~esm1 | < 0.4.2-3ubuntu0.20.04.1~esm1 | < 0.4.8-1ubuntu0.2 | < 0.4.8-4ubuntu0.2 | < 0.6.1-1ubuntu0.2

10 vendors · 181 products

References

79 links
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