Google: sys-kernel/cchost-kernel-6_12, sys-kernel/cchost-kernel-6_18, sys-kernel/csql-kernel-6_12, sys-kernel/csql-kernel-6_18, sys-kernel/lakitu-kernel-6_12, sys-kernel/lakitu-kernel-6_18, sys-kernel/lakitu-nc-kernel-6_12, sys-kernel/lakitu-nc-kernel-6_18: security update to 19862.0.0

critical Tenable Self-Hosted Container Security Plugin ID 470422

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

- 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. (CVE-2026-63984)

Solution

Update the sys-kernel/cchost-kernel-6_12 library and its related packages to version 19862.0.0 or later.

Plugin Details

Severity: Critical

ID: 470422

Version: Revision 1.5

Type: Local

Family: Google COS Security Checks

Published: 10/3/2026

Updated: 10/6/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Medium

Score: 6.9

Percentile: 96.76

Vendor

Vendor Severity: LOW

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-63984

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 6/22/2026

Reference Information

CVE: CVE-2026-63984

Detections

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