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Fencer Intel
critical 9.8

CVE-2020-9366 json

A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49.

published 2020-02-24 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-30187

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.7%
EPSS 2.7% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49. Specially crafted output, or a special program, could corrupt memory and crash Screen or possibly have unspecified other impact.

Patch / fix

  • gnu screen 4.8.0
  • screen Debian 14, Debian 13, Debian 12 4.8.0-1

debian advisories DEBIAN-CVE-2020-9366

  • screen Alpine 3.10, Alpine 3.9, Alpine 3.8 4.6.2-r1
  • screen Alpine 3.11 4.7.0-r1
  • screen Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 4.8.0-r0

alpine advisories ALPINE-CVE-2020-9366

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-9366 updated cvss 6.1

screen: Out of bounds access when setting w_xtermosc after OSC 49

  • Red Hat Enterprise Linux 5 screen Red Hat Enterprise Linux 6 screen Red Hat Enterprise Linux 7 screen
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.71% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.