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NVD / CVE Program· CNA VulnCheck

CVE-2026-9323: Insecure PRNG and Information Exposure in urwid Web Display Backend

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.71% (FIRST EPSS); higher than 53.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: python3-urwid (AlmaLinux:10) 2.5.3-4.el10_2.5; python3-urwid (AlmaLinux:8) 1.3.1-5.el8_10; python3-urwid (AlmaLinux:9) 2.1.2-4.el9_8.1.

Low priority for now. Upgrade to python3-urwid (AlmaLinux:10) 2.5.3-4.el10_2.5; python3-urwid (AlmaLinux:8) 1.3.1-5.el8_10; python3-urwid (AlmaLinux:9) 2.1.2-4.el9_8.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

The urwid web display backend (urwid/display/web.py) generates web session identifiers (urwid_id) in Screen.start() by concatenating two random.randrange(10**9) calls that use Python's Mersenne Twister PRNG, which is not cryptographically secure. Each call consumes approximately 30 bits of PRNG state, and the Mersenne Twister internal state is approximately 19,937 bits, so an attacker who observes approximately 334 session IDs (for example via the X-Urwid-ID HTTP response header) can fully reconstruct the internal state and predict all past and future session IDs (Path B). The same identifier is also used as the filename of a FIFO created in the world-listable /tmp directory (for example /tmp/urwid375487765176907690.in), so any local user on the host can list /tmp to enumerate active session tokens directly (Path A). With a valid session ID, an attacker can read the victim's terminal screen via the polling endpoint, inject keystrokes into the victim's session (yielding OS-level code execution with the session owner's privileges if the session runs a shell), and inject exit sequences or flood the FIFO to terminate or crash the session. A prior Bandit S311 warning on this usage was suppressed with # noqa: S311 rather than fixed

CriticalCVSS 9.2 · v4.0—No exploit Fix available
Published
Jul 18, 2026
Updated
Nov 8, 2026
EPSS
0.7% · 53th percentile

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
36 / 40 · 9.2 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulnCheck
9.2
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-9323

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

  • urwid urwid

    • up to and including 24acd12affected · git

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10python3-urwidbefore 2.5.3-4.el10_2.52.5.3-4.el10_2.5
AlmaLinux:8python3-urwidbefore 1.3.1-5.el8_101.3.1-5.el8_10
AlmaLinux:9python3-urwidbefore 2.1.2-4.el9_8.12.1.2-4.el9_8.1
Debian:12urwidbefore 2.1.2-4+deb12u12.1.2-4+deb12u1
Debian:13urwidfrom 0—
Debian:14urwidbefore 4.1.3-14.1.3-1
openSUSE:Tumbleweedpython-urwidbefore 4.0.5-1.14.0.5-1.1
Red Hat:enterprise_linux_eus:10.0python-urwidbefore 0:2.5.3-4.el10_0.50:2.5.3-4.el10_0.5
Red Hat:enterprise_linux_eus:10.0python-urwid-debugsourcebefore 0:2.5.3-4.el10_0.50:2.5.3-4.el10_0.5
Red Hat:enterprise_linux_eus:10.0python3-urwidbefore 0:2.5.3-4.el10_0.50:2.5.3-4.el10_0.5
Red Hat:enterprise_linux_eus:10.0python3-urwid-debuginfobefore 0:2.5.3-4.el10_0.50:2.5.3-4.el10_0.5
Red Hat:enterprise_linux:10.2python-urwidbefore 0:2.5.3-4.el10_2.50:2.5.3-4.el10_2.5
Red Hat:enterprise_linux:10.2python-urwid-debugsourcebefore 0:2.5.3-4.el10_2.50:2.5.3-4.el10_2.5
Red Hat:enterprise_linux:10.2python3-urwidbefore 0:2.5.3-4.el10_2.50:2.5.3-4.el10_2.5
Red Hat:enterprise_linux:10.2python3-urwid-debuginfobefore 0:2.5.3-4.el10_2.50:2.5.3-4.el10_2.5
Red Hat:enterprise_linux:8::baseospython-urwidbefore 0:1.3.1-5.el8_100:1.3.1-5.el8_10
Red Hat:enterprise_linux:8::baseospython-urwid-debugsourcebefore 0:1.3.1-5.el8_100:1.3.1-5.el8_10
Red Hat:enterprise_linux:8::baseospython3-urwidbefore 0:1.3.1-5.el8_100:1.3.1-5.el8_10
Red Hat:enterprise_linux:8::baseospython3-urwid-debuginfobefore 0:1.3.1-5.el8_100:1.3.1-5.el8_10
Red Hat:enterprise_linux:9::baseospython-urwidbefore 0:2.1.2-4.el9_8.10:2.1.2-4.el9_8.1
Red Hat:enterprise_linux:9::baseospython-urwid-debugsourcebefore 0:2.1.2-4.el9_8.10:2.1.2-4.el9_8.1
Red Hat:enterprise_linux:9::baseospython3-urwidbefore 0:2.1.2-4.el9_8.10:2.1.2-4.el9_8.1
Red Hat:enterprise_linux:9::baseospython3-urwid-debuginfobefore 0:2.1.2-4.el9_8.10:2.1.2-4.el9_8.1
Red Hat:rhel_aus:8.4::baseospython-urwidbefore 0:1.3.1-4.el8_4.10:1.3.1-4.el8_4.1

+28

Same product

urwid: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-103022Urwid: handle_short_request() crashes on non-ASCII POST body (UnicodeEncodeError DoS)
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:python3-urwid2.5.3-4.el10_2.5 · AlmaLinux:10Package registry (OSV)
debian:urwid2.1.2-4+deb12u1 · Debian:12Package registry (OSV)
opensuse:python-urwid4.0.5-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:python-urwid0:1.3.1-4.el8_8.1 · Red Hat:rhel_e4s:8.8::baseosPackage registry (OSV)
red hat:python-urwid-debugsource0:1.3.1-4.el8_8.1 · Red Hat:rhel_e4s:8.8::baseosPackage registry (OSV)
red hat:python3-urwid0:1.3.1-4.el8_8.1 · Red Hat:rhel_e4s:8.8::baseosPackage registry (OSV)
red hat:python3-urwid-debuginfo0:1.3.1-4.el8_8.1 · Red Hat:rhel_e4s:8.8::baseosPackage registry (OSV)
rocky linux:python-urwid0:2.5.3-4.el10_2.5 · Rocky Linux:10Package registry (OSV)
suse:python-urwid2.1.2-150400.11.6.1 · SUSE:Linux Enterprise Module for Python 3 15 SP7Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-338 · Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

CVSS vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records