DEBIAN-CVE-2026-9323
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
DEBIAN-CVE-2026-9323
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-9323
urwid
Source reference: /affected/0/package/name
- Affected versions
- 2.1.2-4
Source reference:
/affected/0/versions - Fixed versions
- 2.1.2-4+deb12u1
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
urwid
Source reference: /affected/1/package/name
- Affected versions
- 2.6.16-1
Source reference:
/affected/1/versions3.0.4-1Source reference:
/affected/1/versions4.1.3-1Source reference:
/affected/1/versions4.2.1-1Source reference:
/affected/1/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
urwid
Source reference: /affected/2/package/name
- Affected versions
- 2.6.16-1
Source reference:
/affected/2/versions3.0.4-1Source reference:
/affected/2/versions - Fixed versions
- 4.1.3-1
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.1.2-4+deb12u1"
}
]
}
],
"package": {
"name": "urwid",
"purl": "pkg:deb/debian/urwid?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"2.1.2-4"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9323.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "urwid",
"purl": "pkg:deb/debian/urwid?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.6.16-1",
"3.0.4-1",
"4.1.3-1",
"4.2.1-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9323.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.3-1"
}
]
}
],
"package": {
"name": "urwid",
"purl": "pkg:deb/debian/urwid?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.6.16-1",
"3.0.4-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9323.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #58419 · Revision 1
- Added to Heist Feed
- Publisher date