GNU flaws being used in attacks

CISA lists 5 flaws in GNU products as being used in attacks, most recently on 26 Jan 2026.

What to do

1. Update every GNU product you use.Install the updates GNU offers, on every device, and restart when asked. Each flaw below has a fix or clear advice; that’s one of CISA’s conditions for listing it.
2. If someone looks after IT for you, send them this page.Many of these are in equipment you don’t see: routers, firewalls, servers, the office network. Ask them to confirm each one is fixed, or that you don’t use the product.
3. Check anything else in the lookup.Search any app, company or CVE. Not being on CISA’s list doesn’t mean safe: keep updating either way.

Every flaw, newest first

1. Being used in attacksAdded by CISA on 26 Jan 2026
   GNU InetUtils
   CVE-2026-24061GNU InetUtils Argument Injection Vulnerability
   GNU InetUtils contains an argument injection vulnerability in telnetd that could allow for remote authentication bypass via a "-f root" value for the USER environment variable.
   CISA’s required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
   CVE recordNVD
2. Being used in attacksAdded by CISA on 2 Oct 2025
   GNU Bash
   CVE-2014-6278GNU Bash OS Command Injection Vulnerability
   GNU Bash contains an OS command injection vulnerability which allows remote attackers to execute arbitrary commands via a crafted environment.
   CISA’s required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
   CVE recordNVD
3. Being used in attacksAdded by CISA on 21 Nov 2023
   GNU C Library
   CVE-2023-4911GNU C Library Buffer Overflow Vulnerability
   GNU C Library's dynamic loader ld.so contains a buffer overflow vulnerability when processing the GLIBC_TUNABLES environment variable, allowing a local attacker to execute code with elevated privileges.
   CISA’s required actionApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
   CVE recordNVD
4. Being used in attacksAdded by CISA on 28 Jan 2022
   GNU Bourne-Again Shell (Bash)
   CVE-2014-7169GNU Bourne-Again Shell (Bash) Arbitrary Code Execution Vulnerability
   GNU Bash through 4.3 processes trailing strings after function definitions in the values of environment variables, which allows remote attackers to execute code. This CVE correctly remediates the vulnerability in CVE-2014-6271.
   CISA’s required actionApply updates per vendor instructions.
   CVE recordNVD
5. Being used in attacksAdded by CISA on 28 Jan 2022
   GNU Bourne-Again Shell (Bash)
   CVE-2014-6271GNU Bourne-Again Shell (Bash) Arbitrary Code Execution Vulnerability
   GNU Bash through 4.3 processes trailing strings after function definitions in the values of environment variables, which allows remote attackers to execute code.
   CISA’s required actionApply updates per vendor instructions.
   CVE recordNVD

From CISA’s Known Exploited Vulnerabilities catalog, updated 21 Oct 2026 (version 2026.10.21). CISA’s required actions are written for US government agencies. GNU on CISA’s site.