Description
A length validation flaw in gdbserver's agent-expression parser allows an unauthenticated remote attacker to read uninitialized heap memory from the gdbserver process and cause a denial of service. Disclosed heap content includes addresses suitable for defeating ASLR in further exploitation.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 6 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat Hardened Images | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | gdb | No fix yet | — |
| Debian 13 | gdb | No fix yet | — |
| Debian 12 | gdb | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | gdb | No fix yet | — |
| Ubuntu 26.04 LTS | gdb | No fix yet | — |
| Ubuntu 24.04 LTS | gdb | No fix yet | — |
| Ubuntu 22.04 LTS | gdb | No fix yet | — |
| Ubuntu 20.04 LTS | gdb | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | gdb | No fix yet | — |
| Ubuntu Pro 16.04 LTS | gdb | No fix yet | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | gdb +1 | No fix yet | — |
References
- https://access.redhat.com/security/cve/CVE-2026-121996 vdb-entry
- RHBZ#2565678 issue-tracking