odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In commit cfddd56 and earlier, an unauthenticated host on the same link can first obtain two bindings through normal DHCPv6 SOLICIT and REQUEST exchanges and then send a crafted RENEW containing multiple IA_NA options. An earlier matched IA consumes most of the response buffer, an unmatched IA causes the build_ia() status branch to write and return a NOBINDING response larger than the remaining space, and a subsequent matched IA is processed after dhcpv6_ia_handle_IAs() subtracts that over-return from an unsigned size_t. The resulting underflow disables subsequent length checks and permits attacker-controlled IA_ADDR serialization beyond the 512-byte stack buffer pdbuf in handle_client_request(). The stack canary terminates odhcpd, and sustained packets can repeatedly disrupt DHCPv6 service while procd respawns the process. The observed configuration does not establish code execution.
CVE-2026-53922
This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (26th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 6.5
- EG Score
- 6.5MEDIUMlow confidence
- EG Risk
- 45EG Risk 45/100
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computed (value × EchelonGraph’s weight)Severity65% × 45%The EG Score, 6.5 of 10.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.3%
- EPSS %ILE
- 26th
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
October 12, 2026
Last Modified
October 13, 2026
Advisory Details (6)
Auto-updated Oct 12, 2026v25.12.5
Patch available: openwrt/openwrt v25.12.5
https://github.com/openwrt/openwrt/releases/tag/v25.12.5odhcpd: pre-auth remote DoS via size_t underflow in dhcpv6_ia_handle_IAs (stack BOF, canary-terminated) · Advisory · openwrt/odhcpd · GitHub
https://github.com/openwrt/odhcpd/security/advisories/GHSA-7hcw-g2jh-pqv5commit d329a1541338 (openwrt/odhcpd)
Fix landed in openwrt/odhcpd commit d329a1541338 — awaiting tagged release
https://github.com/openwrt/odhcpd/commit/d329a15413387027453644cd363dca06ade28328commit d168c27fb6a5 (openwrt/odhcpd)
Fix landed in openwrt/odhcpd commit d168c27fb6a5 — awaiting tagged release
https://github.com/openwrt/odhcpd/commit/d168c27fb6a55a07ac4c888e09ff2f41e263d7b7commit d08dbcc527cb (openwrt/odhcpd)
Fix landed in openwrt/odhcpd commit d08dbcc527cb — awaiting tagged release
https://github.com/openwrt/odhcpd/commit/d08dbcc527cb8f296cd132c1e5bca696e77095b8commit c6792bac3905 (openwrt/odhcpd)
Fix landed in openwrt/odhcpd commit c6792bac3905 — awaiting tagged release
https://github.com/openwrt/odhcpd/commit/c6792bac3905d4bf726d914e9994f6d4b98c5b57Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 26th percentile
- 2026-10-13 14:27 UTCEG score recompute
- 2026-10-13 14:10 UTCEG score recompute
- 2026-10-12 22:28 UTCEG score recompute
- 2026-10-12 21:40 UTCEG score recomputeFirst assessed: 6.5 MEDIUM
- 2026-10-12 21:39 UTCMITRE cvelistV5first tracked
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Dependency Blast Radius
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