Linux: Incorrect Calculation
CVE-2026-46244 is a critical-severity incorrect calculation vulnerability in Linux, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions c161ad9157f5a0429b5ff94d9770faf3bf48d273, 870d59e2cf218e7418491e26bad768cb16654582, 689bbf48c1f45130086ae1c46ab83ea4c753c601 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to c161ad9157f5a0429b5ff94d9770faf3bf48d273 or 870d59e2cf218e7418491e26bad768cb16654582 or 689bbf48c1f45130086ae1c46ab83ea4c753c601 or d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.142 or 6.12.92 or 6.18.34 or 7.0.11, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 3a07327d10a09379315c844c63f27941f5081e0a up to, but not including, c161ad9157f5a0429b5ff94d9770faf3bf48d273; 3a07327d10a09379315c844c63f27941f5081e0a up to, but not including, 870d59e2cf218e7418491e26bad768cb16654582; 3a07327d10a09379315c844c63f27941f5081e0a up to, but not including, 689bbf48c1f45130086ae1c46ab83ea4c753c601; 3a07327d10a09379315c844c63f27941f5081e0a up to, but not including, d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce; 3a07327d10a09379315c844c63f27941f5081e0a up to, but not including, b6a91f68ebfed9c38e0e9150f58a9b85da07181c; 6.2 | c161ad9157f5a0429b5ff94d9770faf3bf48d273, 870d59e2cf218e7418491e26bad768cb16654582, 689bbf48c1f45130086ae1c46ab83ea4c753c601, d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce, b6a91f68ebfed9c38e0e9150f58a9b85da07181c |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Linux | Linux Kernel | 6.2 up to, but not including, 6.6.142; 6.7 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.1 | 6.6.142, 6.12.92, 6.18.34, 7.0.11 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.1 | Critical | CNA |
| CVSS 3.1 | 7.3 | High | CNA |
Official description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_inner: Fix IPv6 inner_thoff desync In nft_inner_parse_l2l3(), when processing inner IPv6 packets, ipv6_find_hdr() correctly computes the transport header offset traversing all extension headers, but the result is immediately overwritten with nhoff + sizeof(_ip6h) (40 bytes), which only accounts for the IPv6 base header. This creates a desync between inner_thoff (wrong — points to extension header start) and l4proto (correct — e.g., IPPROTO_TCP), enabling transport header forgery and potential firewall bypass. This issue affects stable versions from Linux 6.2. For comparison, the normal (non-inner) IPv6 path correctly preserves ipv6_find_hdr()'s result. Removing the incorrect overwrite ensures that ipv6_find_hdr()'s calculated transport header offset is preserved, thereby fixing the desynchronization.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Calculation
The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.
How developers prevent this class of flaw
- Understand your programming language's underlying representation and how it interacts with numeric calculation. Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, not-a-number calculations, and how your language handles numbers that are too large or too small for its underlying representation.
- Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
- Use the appropriate type for the desired action. For example, in C/C++, only use unsigned types for values that could never be negative, such as height, width, or other numbers related to quantity.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/689bbf48c1f45130086ae1c46ab83ea4c753c601
- git.kernel.org/stable/c/870d59e2cf218e7418491e26bad768cb16654582
- git.kernel.org/stable/c/b6a91f68ebfed9c38e0e9150f58a9b85da07181c
- git.kernel.org/stable/c/c161ad9157f5a0429b5ff94d9770faf3bf48d273
- git.kernel.org/stable/c/d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce
Other references
- access.redhat.com/errata/RHSA-2026:33215
- access.redhat.com/errata/RHSA-2026:34094
- access.redhat.com/errata/RHSA-2026:34443
- access.redhat.com/errata/RHSA-2026:34911
- access.redhat.com/errata/RHSA-2026:36018
- access.redhat.com/errata/RHSA-2026:55618
- access.redhat.com/errata/RHSA-2026:55763
- access.redhat.com/errata/RHSA-2026:56225
- access.redhat.com/security/cve/CVE-2026-46244
- bugzilla.redhat.com/show_bug.cgi?id=2484451
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46244.json
Recent Incorrect Calculation vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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