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CVE-2026-99999

CRITICALCVSS 9.3/10EPSS 0.21%

Last modified

CVE-2026-99999 is a critical-severity vulnerability rated 9.3/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: ipv4: validate checksum_start before completing checksum If a packet with bad checksum metadata gets into the ipv4 stack, skb_checksum_help can corrupt the network header and cause a bunch of mischief. This was discovered and reported by Paulos, and has been reporoduced by others independently since. We really shouldn't allow such packets in, but as a defence in depth measure, let's also check before we complete the checksum. A more complete validation at input is forthcoming, but needs more work.. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: validate checksum_start before completing checksum If a packet with bad checksum metadata gets into the ipv4 stack, skb_checksum_help can corrupt the network header and cause a bunch of mischief. This was discovered and reported by Paulos, and has been reporoduced by others independently since. We really shouldn't allow such packets in, but as a defence in depth measure, let's also check before we complete the checksum. A more complete validation at input is forthcoming, but needs more work.

Metrics

CVSS 3.1
9.3/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS Probability
0.21%

10.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= f43798c27684ab925adde7d8acc34c78c6e50df8, < a464d950f31c89565cbaae038cc60db04fe01956; >= f43798c27684ab925adde7d8acc34c78c6e50df8, < 0fab003ef4698e0628060a45a48f14b43ba2a40a; >= f43798c27684ab925adde7d8acc34c78c6e50df8, < 94524b7b32691de2e2ce162c04d6cbc9106e5cbf; >= f43798c27684ab925adde7d8acc34c78c6e50df8, < a65f69e0f38ffbed1b128029e09097436416dc8b; >= f43798c27684ab925adde7d8acc34c78c6e50df8, < 32a8b0adaa18e52aaa0b246b5ffe683075354dbb; >= f43798c27684ab925adde7d8acc34c78c6e50df8, < f3e835af6226f1dd12160cbd696081e9b6155de0; >= f43798c27684ab925adde7d8acc34c78c6e50df8, < c3e33464746166264334641dc850a36eef7e6326; >= f43798c27684ab925adde7d8acc34c78c6e50df8, < 6785011f8b16abf40b1e9d8b2e332232b3e68822
LinuxLinux2.6.27

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-99999?
In the Linux kernel, the following vulnerability has been resolved: ipv4: validate checksum_start before completing checksum If a packet with bad checksum metadata gets into the ipv4 stack, skb_checksum_help can corrupt the network header and cause a bunch of mischief. This was discovered and reported by Paulos, and has been reporoduced by others independently since. We really shouldn't allow such packets in, but as a defence in depth measure, let's also check before we complete the checksum. A more complete validation at input is forthcoming, but needs more work.
How severe is CVE-2026-99999?
CVE-2026-99999 has a CVSS score of 9.3/10 (CRITICAL severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-99999?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST