Use-after-return in `zsock_getaddrinfo()` when a timed-out DNS query is retried without cancellation
CVSS score
7.4
EPSS probability
%0.4
Risk score
0.0
Published
3 mo ago
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Vulnerability description
DayBreach CVE AI Research
CVE-2026-10646 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
Zephyr's BSD-sockets getaddrinfo() implementation (subsys/net/lib/sockets/getaddrinfo.c) passes a pointer to a stack-allocated state object (struct getaddrinfo_state ai_state) as the user_data of an asynchronous DNS resolver query. The socket layer waits on a semaphore with a timeout deliberately set slightly longer than the resolver's own per-query timeout. When that semaphore wait nonetheless times out (-EAGAIN) - which can occur when the resolver's timeout work is delayed by workqueue contention, or in the documented multi-retry configuration where CONFIG_NET_SOCKETS_DNS_TIMEOUT exceeds CONFIG_NET_SOCKETS_DNS_BACKOFF_INTERVAL - the pre-fix code retries the query (goto again) without cancelling the previous one and without resetting the semaphore. The previous query slot remains active in the resolver with its callback and the stack pointer as user_data, and ai_state->dns_id is overwritten so the stale query can no longer be cancelled. A subsequent DNS response delivered over UDP and matched by its 16-bit transaction id (in dispatcher_cb()/dns_read()), or the resolver's own delayed query-timeout work, then invokes dns_resolve_cb() against the now out-of-scope stack frame, writing through the stale pointer (state->status, state->idx, state->ai_arr[], and k_sem_give()). Because the triggering response is network-delivered and its 16-bit id is spoofable/replayable by an on- or off-path attacker, this is a network-influenceable use-after-return that can corrupt reused stack memory, leading to crashes/denial of service or memory corruption. The fix cancels the timed-out query by name and type before retrying and resets the local semaphore, eliminating the stale callback path. Affected: Zephyr v4.0.0 through v4.4.0.
IMPACT: Affected Products and Software
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 7.4 | CVSS V31 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H | NVD |
| 7.4 | CVSS V3_1 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H | CVE CNA |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-10646 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-10646 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
CVSS Vector Radar Chart
7.4 / 10Vulnerability Scoring Details
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:HYama doğrulandı
Weakness Type (CWE & CAPEC)
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