CVE-2026-43190
CVE-2026-43190 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: High (CVSS 3.x base score 8.2)
- EPSS exploit prediction: 0% (37th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-27750
- Weakness: CWE-125
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_tcpmss: check remaining length before reading optlen Quoting reporter: In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads op[i+1] directly without validating the remaining option length. If the last byte of the option field is not EOL/NOP (0/1), the code attempts to index op[i+1]. In the case where i + 1 == optlen, this causes an out-of-bounds read, accessing memory past the optlen boundary (either reading beyond the stack buffer _opt or the following payload).
Frequently asked questions
- What is CVE-2026-43190?
- In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_tcpmss: check remaining length before reading optlen Quoting reporter: In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads op[i+1] directly without validating the remaining option length. If the last byte of the option field is not EOL/NOP (0/1), the code attempts to index op[i+1]. In the case where i + 1 == optlen, this causes an out-of-bounds read, accessing memory past the optlen boundary (either reading beyond the stack buffer _opt or the following payload).
- How severe is CVE-2026-43190?
- CVE-2026-43190 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability high.
- Is CVE-2026-43190 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-43190?
- CVE-2026-43190 primarily affects Linux Linux Kernel. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-43190?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-43190 have an EU (EUVD) identifier?
- Yes. CVE-2026-43190 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27750.
- When was CVE-2026-43190 published?
- CVE-2026-43190 was published on 2026-05-06 and last updated on 2026-06-17.
References
- https://git.kernel.org/stable/c/07a9b32eaae792ff7d0fcac14d8920c937c0a9c3
- https://git.kernel.org/stable/c/5e13d0a37666955b6cfddc0f73cb40ed645b8a05
- https://git.kernel.org/stable/c/735ee8582da3d239eb0c7a53adca61b79fb228b3
- https://git.kernel.org/stable/c/8b300f726640c48c3edfe9c453334dd801f4b74e
- https://git.kernel.org/stable/c/cd5beda7e0e32865e214f28034bb92c1cecff885
- https://git.kernel.org/stable/c/eaedc0bc18be46fe7f58170e967959a932c4f824
- https://git.kernel.org/stable/c/f6c412dcfd76b0516d51aa847d8f4c7b70381b09
- https://git.kernel.org/stable/c/f895191dc32c53eaf443b6443fe40945b2f92287
Affected products (7)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:2.6.12:rc6:*:*:*:*:*:*
More vulnerabilities in Linux Linux Kernel
- CVE-2023-2163 — Critical (CVSS 10.0): Incorrect verifier pruning in BPF in Linux Kernel >=5.4 leads to unsafe code paths being incorrectly marked as safe,…
- CVE-2015-8104 — Critical (CVSS 10.0): The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a…
- CVE-2015-1421 — Critical (CVSS 10.0): Use-after-free vulnerability in the sctp_assoc_update function in net/sctp/associola.c in the Linux kernel before…
- CVE-2014-2523 — Critical (CVSS 10.0): net/netfilter/nf_conntrack_proto_dccp.c in the Linux kernel through 3.13.6 uses a DCCP header pointer incorrectly,…
- CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
- CVE-2010-2521 — Critical (CVSS 10.0): Multiple buffer overflows in fs/nfsd/nfs4xdr.c in the XDR implementation in the NFS server in the Linux kernel before…
All CVEs affecting Linux Linux Kernel →
Other CWE-125 (Out-of-bounds Read) vulnerabilities
- CVE-2026-24826 — Critical (CVSS 10.0): Out-of-bounds Write, Divide By Zero, NULL Pointer Dereference, Use of Uninitialized Resource, Out-of-bounds Read,…
- CVE-2024-22004 — Critical (CVSS 10.0): Due to length check, an attacker with privilege access on a Linux Nonsecure operating system can trigger a…
- CVE-2021-41556 — Critical (CVSS 10.0): sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that…
- CVE-2021-21777 — Critical (CVSS 10.0): An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer…
- CVE-2017-14451 — Critical (CVSS 10.0): An exploitable out-of-bounds read vulnerability exists in libevm (Ethereum Virtual Machine) of CPP-Ethereum. A…
- CVE-2013-0767 — Critical (CVSS 10.0): The nsSVGPathElement::GetPathLengthScale function in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and…