Quagga: An off-by-one out-of-bounds write vulnerability
Affects quaggaSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 8.1-1ubuntu1.16 : patch quagga soon.
Data as of 5 Nov 2026, 22:37 UTC
- Patch
- Available – fixed in 8.1-1ubuntu1.16, 8.4.4-1.1ubuntu6.7, 10.4.1-3ubuntu1.4 +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSfrrpkg:deb/ubuntu/frr?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 25.10frrpkg:deb/ubuntu/frr?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSfrrpkg:deb/ubuntu/frr?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSfrrpkg:deb/ubuntu/frr?arch=source&distro=jammyOther threats | Affected
| Fixed in
|
Ubuntu 20.04 LTSquaggapkg:deb/ubuntu/quagga?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSfrrpkg:deb/ubuntu/frr?arch=source&distro=esm-apps/focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and can be applied by updating to the patched package versions: 8.1-1ubuntu1.16, 8.4.4-1.1ubuntu6.7, 10.4.1-3ubuntu1.4, or 10.5.1-1ubuntu4.1 as per the Ubuntu security notice USN-8376-1. Applying these updates will remediate the vulnerability and prevent denial of service attacks exploiting this flaw.
Description
An off-by-one out-of-bounds write vulnerability exists in the bgp_flowspec_op_decode() function of FRRouting (FRR) stable/10.0. This flaw allows attackers to cause a denial of service (DoS) by supplying a crafted FlowSpec component. The issue affects multiple versions of the Quagga package as used in Ubuntu distributions. Fixed versions are available and updating to these versions mitigates the vulnerability.