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CVE-2026-55606

MEDIUM 6.5

Published 2026-10-23 · Last modified 2026-10-23

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In versions 25.12 and prior, odhcpd's DHCPv6 self-loop detection at dhcpv6.c:720 uses a network-byte-order DUID length value directly as the memcmp() size parameter. On little-endian hosts, this causes memcmp() to read far beyond the stack buffer — a single unauthenticated DHCPv6 packet triggers a 2560-byte overread from a 128-byte buffer. At time of publication, there are no publicly available patches.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.4%chance of exploitation in 30 days · 32nd percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

6.5CVSS 3.1 · MEDIUM

  • ConfidentialityLow
  • IntegrityNone
  • AvailabilityLow

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

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Data snapshot:

Affected

Vendors Openwrt

Products Odhcpd

Weakness (CWE)

  • CWE-126: : Buffer Over-read

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

References and research data (JSON)

All CVSS metrics

  • MEDIUM 6.5 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
  • MEDIUM 6.5 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS