In the Linux kernel, the following vulnerability has been resolved: tls: make sure to abort the stream if headers are bogus Normally we wait for the socket to buffer up the whole record before we service it. If the socket has a tiny buffer, however, we read out the data sooner, to prevent connection stalls. Make sure that we abort the connection when we find out late that the record is actually invalid. Retrying the parsing is fine in itself but since we copy some more data each time before we parse we can overflow the allocated skb space. Constructing a scenario in which we're under pressure without enough data in the socket to parse the length upfront is quite hard. syzbot figured out a way to do this by serving us the header in small OOB sends, and then filling in the recvbuf with a large normal send. Make sure that tls_rx_msg_size() aborts strp, if we reach an invalid record there's really no way to recover.
Conclusion & alert: CVE-2025-39946 is rated High Risk (77.3/100): CVSS Critical severity, with high exploitation likelihood (EPSS 9.07%, 95th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +9.05% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.02% | 9.07% | +9.05% |
| 2 | 2025-10-04 | — | 0.02% | — |
Full EPSS history (2 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
| 5.5 | 3.1 | MEDIUM |
|
1.8 | 3.6 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
unimportant | CVE-2025-39946 unimportant priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. | https://security-tracker.debian.org/tracker/CVE-2025-39946 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2025-39946 |
suse
|
medium | CVE-2025-39946 severity moderate: SUSE including 466 source package names (2.1.3-6.88:kernel-default-base-6.4.0-36.1.21.13, 2.1.3-7.105:kernel-rt-6.4.0-38.1, …), 1021 product×package rows across 207 product lines (Container suse/sl-micro/6.0/base-os-container, Container suse/sl-micro/6.0/kvm-os-container, … (207 product lines)): Fixed 619, Known Affected 231, Known Not Affected 150, First Fixed 21. | https://www.suse.com/security/cve/CVE-2025-39946/ |
ubuntu
|
medium | CVE-2025-39946 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1414 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1017, ignored 164, released 128, not-affected 96, pending 4, needed 3, needs-triage 2. | https://ubuntu.com/security/CVE-2025-39946 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| linux | linux_kernel | >= 6.0, < 6.1.154 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.2, < 6.6.108 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.7, < 6.12.49 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.13, < 6.16.9 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | 6.17 | cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* |
| linux | linux_kernel | 6.17 | cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* |
| linux | linux_kernel | 6.17 | cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* |
| linux | linux_kernel | 6.17 | cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* |
| linux | linux_kernel | 6.17 | cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* |
| linux | linux_kernel | 6.17 | cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:* |