Integer Overflow or Wraparound Affecting kernel-zfcpdump-devel-matched package, versions *


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.51% (41st percentile)

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  • Snyk IDSNYK-RHEL10-KERNELZFCPDUMPDEVELMATCHED-18560586
  • published6 Aug 2026
  • disclosed19 Jul 2026

Introduced: 19 Jul 2026

NewCVE-2026-63984  (opens in a new tab)
CWE-190  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 kernel-zfcpdump-devel-matched.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-zfcpdump-devel-matched package and not the kernel-zfcpdump-devel-matched package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress()

ipv6_rpl_srh_decompress() computes:

outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3);

hdrlen is __u8. For n >= 127 the result exceeds 255 and silently truncates. With n=127 (cmpri=15, cmpre=15, pad=0, hdrlen=16):

(128 * 16) >> 3 = 256, truncated to 0 as __u8

The caller in ipv6_rpl_srh_rcv() then places the compressed header at buf + ((ohdr->hdrlen + 1) << 3). With hdrlen=0 this is buf + 8, but the decompressed region occupies buf[0..2055] (8-byte header plus 128 full addresses). The compressed header overlaps the decompressed data, and ipv6_rpl_srh_compress() writes into this overlap, corrupting the routing header of the forwarded packet.

The existing guard at exthdrs.c:546 checks (n + 1) > 255, which prevents n+1 from overflowing unsigned char (the segments_left field), but does not prevent the computed hdrlen from overflowing __u8. n=127 passes because 128 <= 255, yet hdrlen=256 does not fit.

Tighten the bound to (n + 1) > 127. This caps n at 126, giving hdrlen = (127 * 16) >> 3 = 254, which fits in __u8. The compressed header then lands at buf + ((254 + 1) << 3) = buf + 2040, exactly past the decompressed region (buf[0..2039]). No overlap. 127 segments is well beyond any realistic RPL deployment.

CVSS Base Scores

version 3.1