Description
An issue was discovered in Botan 1.11.32 through 2.x before 2.6.0. An off-by-one error when processing malformed TLS-CBC ciphertext could cause the receiving side to include in the HMAC computation exactly 64K bytes of data following the record buffer, aka an over-read. The MAC comparison will subsequently fail and the connection will be closed. This could be used for denial of service. No information leak occurs.
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 13 | botan | 2.4.0-6 | — |
| Debian 12 | botan | 2.4.0-6 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | botan | No fix yet | — |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 14.04 LTS | botan1.10 | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | Botan | 2.18.1-1.3 | openSUSE-SU-2024:10594-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.21 | botan | 2.6.0-r0 | — |
| Alpine v3.20 | botan | 2.6.0-r0 | — |
| Alpine v3.19 | botan | 2.6.0-r0 | — |
| Alpine v3.18 | botan | 2.6.0-r0 | — |
| Alpine v3.17 | botan | 2.6.0-r0 | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.16 | botan | 2.6.0-r0 | — |
| Alpine v3.15 | botan | 2.6.0-r0 | — |
| Alpine v3.14 | botan | 2.6.0-r0 | — |
| Alpine v3.13 | botan | 2.6.0-r0 | — |
| Alpine v3.12 | botan | 2.6.0-r0 | — |
| Alpine v3.11 | botan | 2.6.0-r0 | — |
| Alpine v3.10 | botan | 2.6.0-r0 | — |
Advisories 1
- openSUSE-SU-2024:10594-1 Botan-2.18.1-1.3 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026