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Fencer Vulns
medium 6.9

CVE-2009-1897 json

The tun_chr_poll function in drivers/net/tun.c in the tun subsystem in the Linux kernel 2.6.30 and 2.6.30.1, when the -fno-delete-null-poin…

published 2009-07-20 17 y ago modified 2026-06-16 4 mo ago also EUVD-2009-1892

cvss
6.9
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
2
Exploit-DB

Summary

The tun_chr_poll function in drivers/net/tun.c in the tun subsystem in the Linux kernel 2.6.30 and 2.6.30.1, when the -fno-delete-null-pointer-checks gcc option is omitted, allows local users to gain privileges via vectors involving a NULL pointer dereference and an mmap of /dev/net/tun, a different vulnerability than CVE-2009-1894.

Patch / fix

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-1897 updated cvss 6.9

kernel: tun/tap: Fix crashes if open() /dev/net/tun and then poll() it

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. First public exploit (EDB-33088)
  2. Published

Exploit prediction

1.52% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-33088 Linux Kernel 2.6.30 - 'tun_chr_pool()' Null Pointer Dereference dos, 2009-06-17
  • EDB-9191 Linux Kernel 2.6.30 < 2.6.30.1 / SELinux (RHEL 5) - Local Privilege Escalation local, 2009-07-17
  • isc.sans.org http://isc.sans.org/diary.html?storyid=6820 referenced PoC, tagged "exploit" by a source, unverified
  • lkml.org http://lkml.org/lkml/2009/7/6/19 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 6.9 AV:L/AC:M/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.