Answer in brief
CVE-2025-39946 records a Critical severity (CVSS 9.8) vulnerability in tls: make sure to abort the stream if headers are bogus. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=84c61fe1a75b4255df1e1e7c054c9e6d048da417 <b36462146d86b1f22e594fe4dae611dffacfb203 || >=84c61fe1a75b4255df1e1e7c054c9e6d048da417 <4cefe5be73886f383639fe0850bb72d5b568a7b9 || >=84c61fe1a75b4255df1e1e7c054c9e6d048da417 <208640e6225cc929a05adbf79d1df558add3e231 || >=84c61fe1a75b4255df1e1e7c054c9e6d048da417 <61ca2da5fb8f433ce8bbd1657c84a86272133e6b || >=84c61fe1a75b4255df1e1e7c054c9e6d048da417 <0aeb54ac4cd5cf8f60131b4d9ec0b6dc9c27b20d | b36462146d86b1f22e594fe4dae611dffacfb203, 4cefe5be73886f383639fe0850bb72d5b568a7b9, 208640e6225cc929a05adbf79d1df558add3e231, 61ca2da5fb8f433ce8bbd1657c84a86272133e6b, 0aeb54ac4cd5cf8f60131b4d9ec0b6dc9c27b20d |
| Linux/Linuxgeneric | 6.0 | Not reported |
Published upstream
Oct 4, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.