Vulnerability · Published Sep 23, 2026 · Assigned by redhat
CVE-2026-88840Busybox: busybox: tls ssl_server reads one byte out of bounds when parsing truncated clienthello
Medium 5.3
In plain English
A medium-severity out-of-bounds read in Red Hat Hardened Images from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities).
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.2%top 89.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
BusyBox TLS get_client_hello() reads past the end of the input buffer when parsing a truncated ClientHello message.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:14 | busybox | no fix listed | DEBIAN-CVE-2026-88840 |
| Ubuntu:22.04:LTS | busybox | no fix listed | UBUNTU-CVE-2026-88840 |
| Ubuntu:24.04:LTS | busybox | no fix listed | UBUNTU-CVE-2026-88840 |
| Ubuntu:26.04:LTS | busybox | no fix listed | UBUNTU-CVE-2026-88840 |
| Ubuntu:26.10 | busybox | no fix listed | UBUNTU-CVE-2026-88840 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Red Hat | Red Hat Hardened Images | see references |
Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
References
- https://access.redhat.com/security/cve/CVE-2026-88840 vdb-entry, x_refsource_REDHAT
- RHBZ#2531354 issue-tracking, x_refsource_REDHAT