VulnerabilityPublished 11 Nov 2026

CVE-2026-119194: python-pyasn1 security update

Affects python-pyasn1Source GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-119194· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade to 0.5.1-5.oe2403sp4 soon.

Data as of 11 Nov 2026, 14:48 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	7.5

Patch: Available – fixed in 0.5.1-5.oe2403sp4

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade python-pyasn1 to 0.5.1-5.oe2403sp4.

Affected software

Product	Affected	Fixed in
openEuler 24.03-LTS-SP4python-pyasn1`pkg:rpm/openEuler/python-pyasn1&distro=openEuler-24.03-LTS-SP4`Other threats	Affected <0.5.1-5.oe2403sp4	Fixed in 0.5.1-5.oe2403sp4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade python-pyasn1 to version 0.6.5 or later, where these CPU exhaustion vulnerabilities have been fixed. No other mitigation is required as the issues are resolved in this official fix.

Description

The python-pyasn1 library, used for ASN.1 data decoding in Python, contains multiple vulnerabilities prior to version 0.6.5 that cause excessive CPU consumption during decoding of attacker-controlled inputs. These issues arise from quadratic-time operations when processing certain ASN.1 types such as schemaless containers, constructed strings, BIT STRINGs, and binary REAL values. Exploitation can lead to CPU exhaustion and reduced service availability without impacting confidentiality or integrity. The vulnerabilities are fixed in version 0.6.5.

Impact

Successful exploitation of these vulnerabilities can cause denial of service by exhausting CPU resources during ASN.1 decoding operations. This can reduce service availability but does not affect data confidentiality or integrity. The attack requires attacker-controlled ASN.1 input with specific crafted structures to trigger quadratic CPU usage.

Summary

The python-pyasn1 library versions before 0.6.5 suffer from multiple denial-of-service vulnerabilities due to inefficient decoding algorithms that exhibit quadratic CPU complexity when processing specially crafted ASN.1 BER, CER, or DER inputs. Specifically, schemaless container decoding stores TagSets in a growing set causing quadratic comparisons (CVE-2026-119194). Constructed OCTET STRING and indefinite-length ANY decoding repeatedly concatenate fragments inefficiently (CVE-2026-119195). Constructed BIT STRING decoding repeatedly shifts and copies an accumulating bit value causing quadratic work (CVE-2026-119196). Binary REAL decoding builds a large mantissa one octet at a time with repeated shifts and copies, leading to prolonged CPU usage (CVE-2026-119197). These flaws allow an attacker to exhaust CPU resources during decoding, impacting availability but not confidentiality or integrity. All these issues are resolved in pyasn1 version 0.6.5.

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What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Nov 2026, 14:48 UTC

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