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Fencer Vulns
high 7.3

CVE-2023-34100 json

Out-of-Bounds Read in contiki-ng

published 2023-06-09 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-38206

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

Contiki-NG is an open-source, cross-platform operating system for IoT devices. When reading the TCP MSS option value from an incoming packet, the Contiki-NG OS does not verify that certain buffer indices to read from are within the bounds of the IPv6 packet buffer, uip_buf. In particular, there is a 2-byte buffer read in the module os/net/ipv6/uip6.c. The buffer is indexed using 'UIP_IPTCPH_LEN + 2 + c' and 'UIP_IPTCPH_LEN + 3 + c', but the uip_buf buffer may not have enough data, resulting in a 2-byte read out of bounds. The problem has been patched in the "develop" branch of Contiki-NG, and is expected to be included in release 4.9. Users are advised to watch for the 4.9 release and to upgrade when it becomes available. There are no workarounds for this vulnerability aside from manually patching with the diff in commit `cde4e9839`.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
22 mo ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

Affected products

  • contiki-ng contiki-ng

Classification

Weakness

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.