CVE-2007-4567

Published Dec 21, 2007

Last updated 3 months ago

Overview

Description
The ipv6_hop_jumbo function in net/ipv6/exthdrs.c in the Linux kernel before 2.6.22 does not properly validate the hop-by-hop IPv6 extended header, which allows remote attackers to cause a denial of service (NULL pointer dereference and kernel panic) via a crafted IPv6 packet.
Source
secalert@redhat.com
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 2.0

Type
Primary
Base score
7.8
Impact score
6.9
Exploitability score
10
Vector string
AV:N/AC:L/Au:N/C:N/I:N/A:C

Weaknesses

nvd@nist.gov
CWE-20

Social media

Hype score
Not currently trending

Vendor comments

  • Red HatThis issue did not affect the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 3, 4 and Red Hat Enterprise MRG. Shipped kernels do not include upstream commit a11d206d that introduced the problem. This upstream commit was backported in Red Hat Enterprise Linux 5 via RHBA-2008:0314. It was reported and addressed in Red Hat Enterprise Linux 5 via https://rhn.redhat.com/errata/RHSA-2010-0019.html

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.CVE-2026-53362

References

Sources include official advisories and independent security research.