Search/CVE-2025-39946
● CVE — Critical

CVE-2025-39946

VendorlinuxProductlinux kernelDiscoveredOct 4, 2025UpdatedApr 6, 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…

CVSS v3.1
9.8 CRITICAL
EPSS
10.3%
probability of exploitation in 30 days
CISA KEV
Not listed
no confirmed exploitation reported
News coverage
20
sources referencing this CVE
Related IOCs
0
seen in the same coverage
EPSS Trend
Aug 16, 2026 → Oct 25, 2026
▲ 1.32pp
8.94% → 10.3% over 3 tracked changes
CVSS v3.1 Detail
Attack VectorNETWORK
Attack ComplexityLOW
Privileges RequiredNONE
User InteractionNONE
ScopeUNCHANGED
ConfidentialityHIGH
IntegrityHIGH
AvailabilityHIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Connections
21 relationships
Timeline
disclosure → media coverage
Oct 4, 2025
Disclosure — published as a CVE record. · last revised by NVD Apr 6, 2026
Dec 10, 2025
ubuntu.com reports: USN-7921-1: Linux kernel vulnerabilities
Dec 15, 2025
ubuntu.com reports: USN-7934-1: Linux kernel (Azure) vulnerabilities
Dec 15, 2025
ubuntu.com reports: USN-7936-1: Linux kernel (OEM) vulnerabilities
Dec 19, 2025
ubuntu.com reports: USN-7921-2: Linux kernel (Real-time) vulnerabilities
Feb 11, 2026
ubuntu.com reports: USN-8028-1: Linux kernel vulnerabilities
Feb 12, 2026
ubuntu.com reports: USN-8028-2: Linux kernel (Real-time) vulnerabilities
Feb 12, 2026
ubuntu.com reports: USN-8031-1: Linux kernel (GCP) vulnerabilities
Feb 17, 2026
ubuntu.com reports: USN-8028-3: Linux kernel (Real-time) vulnerabilities
Feb 17, 2026
ubuntu.com reports: USN-8028-4: Linux kernel (FIPS) vulnerabilities
Feb 17, 2026
ubuntu.com reports: USN-8028-5: Linux kernel vulnerabilities
Feb 18, 2026
ubuntu.com reports: USN-8031-2: Linux kernel (GCP FIPS) vulnerabilities
Feb 19, 2026
ubuntu.com reports: USN-8028-6: Linux kernel (HWE) vulnerabilities
Feb 19, 2026
ubuntu.com reports: USN-8031-3: Linux kernel vulnerabilities
Feb 19, 2026
ubuntu.com reports: USN-8052-1: Linux kernel (Low Latency) vulnerabilities
Feb 19, 2026
ubuntu.com reports: USN-8028-7: Linux kernel (Low Latency NVIDIA) vulnerabilities
Feb 24, 2026
ubuntu.com reports: USN-8028-8: Linux kernel (IBM) vulnerabilities
Feb 24, 2026
ubuntu.com reports: USN-8052-2: Linux kernel (Xilinx) vulnerabilities
Mar 4, 2026
ubuntu.com reports: USN-8074-1: Linux kernel (Azure) vulnerabilities
Mar 4, 2026
ubuntu.com reports: USN-8074-2: Linux kernel (Azure FIPS) vulnerabilities
Mar 25, 2026
ubuntu.com reports: USN-8126-1: Linux kernel (Azure) vulnerabilities
Public PoC (1)
Unverified third-party code — review before executing.