CVE-2021-26937
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (9.15%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 9.15% probability · 95th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-88
- Affected
- gnu/screen · debian/debian linux · fedoraproject/fedora
- Source
- cve@mitre.org
EPSS 9.1% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.openwall.com/lists/oss-security/2021/02/09/8Exploit, Mailing List, Third Party Advisory
- https://ftp.gnu.org/gnu/screen/Product
- https://lists.debian.org/debian-lts-announce/2021/02/msg00031.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNWBOIDEPOEQS5RMQVMFKHKXJCGNYWBL/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JJWLXP45POUUYBJRRWPVAWNZDJTLYWVM/
- https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00000.htmlExploit, Mailing List, Vendor Advisory
- https://security.gentoo.org/glsa/202105-11Third Party Advisory
- https://www.debian.org/security/2021/dsa-4861Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/02/09/3Exploit, Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/02/09/8Exploit, Mailing List, Third Party Advisory
- https://ftp.gnu.org/gnu/screen/Product
- https://lists.debian.org/debian-lts-announce/2021/02/msg00031.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNWBOIDEPOEQS5RMQVMFKHKXJCGNYWBL/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JJWLXP45POUUYBJRRWPVAWNZDJTLYWVM/
- https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00000.htmlExploit, Mailing List, Vendor Advisory
- https://security.gentoo.org/glsa/202105-11Third Party Advisory
- https://security.netapp.com/advisory/ntap-20250509-0004/
- https://www.debian.org/security/2021/dsa-4861Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/02/09/3Exploit, Mailing List, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.