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VulnerabilityPublished Updated

CVE-2026-9323: urwid · PRNG

Affects urwidSource CVE Database V5

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Not known to be exploited · CVSS 9.2 Critical · patch available : patch urwid as a priority.

Data as of 8 Nov 2026, 14:21 UTC

CVSS 4.0 base score
9.2Critical
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.09.2
CNA (VulnCheck)CVSS 3.18.1
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-07-20.

Patch
Available
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 8 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
urwidurwidAffected
  • =0
Fixed in–

AI-suggested

A patch is available for this vulnerability and should be applied to mitigate the risk. Since the vulnerability arises from the use of a cryptographically weak PRNG for session ID generation and insecure session ID handling, upgrading to the fixed version is the recommended remediation. No vendor advisory content contradicts this; thus, patching is the primary mitigation.

Description

CVE-2026-9323 is a critical vulnerability in the urwid library where the web session identifiers are generated using Python's Mersenne Twister PRNG, which is not cryptographically secure. This weakness allows an attacker to reconstruct the internal PRNG state after observing approximately 334 session IDs, enabling prediction of past and future session IDs. Additionally, session IDs are used as filenames for FIFOs in a world-listable /tmp directory, allowing local users to enumerate active sessions. Exploitation can lead to reading the victim's terminal screen, injecting keystrokes to execute code with the victim's privileges, or crashing the session. A prior security warning was suppressed rather than addressed. A patch is available, and the vulnerability affects urwid version 0.

References

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