CVE-2008-1673

Published Jun 10, 2008

Last updated 3 months ago

Overview

Description
The asn1 implementation in (a) the Linux kernel 2.4 before 2.4.36.6 and 2.6 before 2.6.25.5, as used in the cifs and ip_nat_snmp_basic modules; and (b) the gxsnmp package; does not properly validate length values during decoding of ASN.1 BER data, which allows remote attackers to cause a denial of service (crash) or execute arbitrary code via (1) a length greater than the working buffer, which can lead to an unspecified overflow; (2) an oid length of zero, which can lead to an off-by-one error; or (3) an indefinite length for a primitive encoding.
Source
secalert@redhat.com
NVD status
Modified
Products
debian_linux, linux_kernel

Risk scores

CVSS 2.0

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

Weaknesses

nvd@nist.gov
CWE-119

Social media

Hype score
Not currently trending

Vendor comments

  • Red HatNot vulnerable. This issue did not affect the versions of Linux kernel as shipped with Red Hat Enterprise Linux 2, 3, 4, 5 or Red Hat Enterprise MRG. The but existed on Red Hat Enterprise Linux 3, 4, and 5. However, this is only a security issue if the SLOB or SLUB memory allocators were used (introduced in Linux kernel versions 2.6.16 and 2.6.22, respectively). All Red Hat Enterprise Linux and Red Hat Enterprise MRG kernels use the SLAB memory allocator, which in this case, cannot be exploited to allow arbitrary code execution. As a preventive measure, the underlying bug was addressed in Red Hat Enterprise Linux 3, 4, and 5, via the advisories RHSA-2008:0973, RHSA-2008:0508, and RHSA-2008:0519, respectively.

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.