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CVE-2026-99030

HIGHCVSS 7.5/10

Last modified

CVE-2026-99030 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: net: skbuff: don't leave stale bytes in skb_copy_and_csum_bits() When skb_copy_and_csum_bits() reaches unreadable frags it returns 0 after copying only the linear part, and the rest of the caller's buffer is left as it was. The callers copy into a buffer that is about to go out on the wire: an ICMP error quoting the offending packet, or a driver's TX bounce buffer in skb_copy_and_csum_dev().

Description

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: don't leave stale bytes in skb_copy_and_csum_bits() When skb_copy_and_csum_bits() reaches unreadable frags it returns 0 after copying only the linear part, and the rest of the caller's buffer is left as it was. The callers copy into a buffer that is about to go out on the wire: an ICMP error quoting the offending packet, or a driver's TX bounce buffer in skb_copy_and_csum_dev(). Neither buffer is zeroed beforehand, so whatever was in memory there gets sent. Zero the part of the buffer we didn't fill. The checksum usually won't match the data any more, so the receiver will usually drop the packet, but either way it no longer carries anything it shouldn't. Only zero for a positive @len, a negative one from a broken caller must not turn into a huge memset().

Metrics

CVSS 3.1
7.5/10

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

Affected Software

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

VendorProductVersions
LinuxLinux>= 65249feb6b3df9e17bab5911ee56fa7b0971e231, < 5f19b9cfff79508e8cb09be40d014cb0807f3854; >= 65249feb6b3df9e17bab5911ee56fa7b0971e231, < 5551399751e2c9f31e4f3428040985a07e79d9c2; >= 65249feb6b3df9e17bab5911ee56fa7b0971e231, < 39d1a6b601831237c6038b5e3ac8dbb883c1700a; >= 65249feb6b3df9e17bab5911ee56fa7b0971e231, < ab9414ed70bd783e902a85c350620dee269bcb2b
LinuxLinux6.12

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-99030?
In the Linux kernel, the following vulnerability has been resolved: net: skbuff: don't leave stale bytes in skb_copy_and_csum_bits() When skb_copy_and_csum_bits() reaches unreadable frags it returns 0 after copying only the linear part, and the rest of the caller's buffer is left as it was. The callers copy into a buffer that is about to go out on the wire: an ICMP error quoting the offending packet, or a driver's TX bounce buffer in skb_copy_and_csum_dev(). Neither buffer is zeroed beforehand, so whatever was in memory there gets sent. Zero the part of the buffer we didn't fill. The checksum usually won't match the data any more, so the receiver will usually drop the packet, but either way it no longer carries anything it shouldn't. Only zero for a positive @len, a negative one from a broken caller must not turn into a huge memset().
How severe is CVE-2026-99030?
CVE-2026-99030 has a CVSS score of 7.5/10 (HIGH severity).
How do I fix CVE-2026-99030?
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