A DHCP server, or anyone on the LAN who answers a DISCOVER first, can make the client read about...
Summary
Vulnerability reported (CVE-2026-102720). Risk of unauthorized operations or information disclosure. Exploitable via data.
Original description
The description as published by the source.
A DHCP server, or anyone on the LAN who answers a DISCOVER first, can make the client read about a
kilobyte past the end of the received message.
The option walk keeps a pointer and an offset in step, and the only bound check uses the offset:
/* addons/dhcp/nxd_dhcp_client.c:7538, 7572 */
while (i < length - 1)
{
...
size = *(++data); /* data moves 1: type -> length byte */
data += size + 1; /* data moves size + 1 more */
i += size + 1; /* i moves only size + 1 */
}
A TLV option occupies size + 2 bytes. data is advanced by size + 2 in total, i by size + 1, so
the offset falls one byte behind the real read position for every option the walk skips. After
enough skipped options the check i < length - 1 still holds while data is already past the end
of the message, and the subsequent read of the type and length bytes comes from whatever follows.
A single OFFER carrying a long run of skippable options is enough:
ERROR: AddressSanitizer: heap-buffer-overflow
READ of size 1 at 0x61b000000794 thread T5
#0 _nx_dhcp_search_buffer addons/dhcp/nxd_dhcp_client.c:7541
#1 _nx_dhcp_get_option_value addons/dhcp/nxd_dhcp_client.c:7082
0x61b000000794 is located 164 bytes to the right of 1648-byte region
A well formed OFFER through the same path is handled normally, the client records the offer and
moves to REQUESTING, so the difference is the option layout rather than the harness.…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-102720 has been found.
Attackers can target a specific entry point like data over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "CVE-2026-102720" on the vendor's site.
CVE-2026-102720 — CWE-125
Attack surface: data
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) has been reported. Attackers reach the vulnerable code path via data.
Check the vendor advisory for the affected versions. Attack surface: data.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで影響コンポーネントを特定する。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web github.com
- web nvd.nist.gov
- web github.com