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TI-2021-08542 Aliases CVE-2021-26937GHSA-pjrj-fmxp-cmc4

encoding.c in GNU Screen through 4.8.0 allows remote attackers to cause a denial of…

Priority MEDIUM 54CWE-88Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 6 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-88.

Summary

encoding.c in GNU Screen through 4.8.0 allows remote attackers to cause a denial of service (invalid write access and application crash) or possibly have unspecified other impact via a crafted UTF-8 character sequence.

Why it matters now

EPSS 0.09256 95th percentileScored 2026-11-07
Public exploit Yes 3 exploit referencesTagged by NVD
Fix Partial Red Hat: 2 advisoriesRed Hat: 6 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:a:gnu:screen:*:*:*:*:*:*:*:*up to 4.8.0VulnerableGNU
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*10.0VulnerableDebian
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*32VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
  • cpe:2.3:a:gnu:screen:*:*:*:*:*:*:*:* Versions up to 4.8.0 Vulnerable ·GNU
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
  • cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
  • cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject

Remediation

Red Hat 2 advisories

  • RHSA-2022:1074 Released 2022-03-28 · Red Hat rating Important
    screen security update
    • Red Hat Enterprise Linux Server AUS (v. 7.7) screen-4.1.0-0.25.20120314git3c2946.el7_7.1
    • Red Hat Enterprise Linux Server E4S (v. 7.7) screen-4.1.0-0.25.20120314git3c2946.el7_7.1
    • Red Hat Enterprise Linux Server TUS (v. 7.7) screen-4.1.0-0.25.20120314git3c2946.el7_7.1
  • RHSA-2021:0742 Released 2021-03-08 · Red Hat rating Important
    screen security update
    • Red Hat Enterprise Linux Client Optional (v. 7) screen-4.1.0-0.27.20120314git3c2946.el7_9
    • Red Hat Enterprise Linux Server (v. 7) screen-4.1.0-0.27.20120314git3c2946.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) screen-4.1.0-0.27.20120314git3c2946.el7_9

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2021:0742
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2021:0742
Red Hat Enterprise Linux Server AUS (v. 7.7)Fixed RHSA-2022:1074
Red Hat Enterprise Linux Server E4S (v. 7.7)Fixed RHSA-2022:1074
Red Hat Enterprise Linux Server TUS (v. 7.7)Fixed RHSA-2022:1074
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:0742

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-26937
  2. 2026-10-03 Alias added: GHSA-pjrj-fmxp-cmc4

References

Exploit 3

Advisory 5

Other 1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences