VulnerabilityPublished 21 Sep 2026

CVE-2026-16651: Temporal Technologies temporalio/sqlparser · Improper Validation of Array Index

Affects Temporal Technologies temporalio/sqlparserSource CVE Database V5

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Not known to be exploited · CVSS 8.7 High : upgrade to 0.0.0-20260721183040-74181ffcbaaf soon.

Data as of 5 Nov 2026, 00:01 UTC

CVSS 4.0 base score

8.7High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.0.0-20260721183040-74181ffcbaaf, 1.31.3, 1.30.7

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: High
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: High: There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the Vulnerable System (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade temporalio/sqlparser and github.com/temporalio/sqlparser to 0.0.0-20260721183040-74181ffcbaaf; Temporal Server and go.temporal.io/server to 1.31.3 or 1.30.7.

Affected software

Product	Affected	Fixed in
Temporal Technologies, Inc.temporalio/sqlparser	Affected >=0.0.0-20180604150908-b055e9c9b4fa <0.0.0-20260721183040-74181ffcbaaf	Fixed in 0.0.0-20260721183040-74181ffcbaaf
Temporal Technologies, Inc.Temporal Server	Affected >=1.29.0 <=1.29.7 >=1.30.0 <1.30.7 >=1.31.0 <1.31.3	Fixed in 1.31.3 1.30.7
Gogithub.com/temporalio/sqlparser`pkg:golang/github.com/temporalio/sqlparser`Other threats	Affected >=0.0.0-20180604150908-b055e9c9b4fa <0.0.0-20260721183040-74181ffcbaaf	Fixed in 0.0.0-20260721183040-74181ffcbaaf
Gogo.temporal.io/server`pkg:golang/go.temporal.io/server`Other threats	Affected >=1.29.0 <=1.29.7 >=1.30.0 <1.30.7 >=1.31.0 <1.31.3	Fixed in 1.30.7 1.31.3

CPE configurations (1)

cpe:2.3:a:temporal:temporal:*:*:*:*:*:*:*:*

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AI-suggested

If you cannot patch yet, restrict access to the ListWorkers API to trusted users only and monitor for abnormal termination of the Matching process. Applications should implement recovery mechanisms for panics in parsing goroutines if possible.

Description

temporalio/sqlparser can panic when Parse, ParseStrictDDL, or ParseNext processes a MySQL version comment whose contents are empty or consist only of one to five decimal digits. ExtractMysqlComment does not check the -1 result returned by strings.IndexFunc before using it as a slice boundary. The resulting Go runtime panic propagates unless the caller recovers it on the parsing goroutine, so applications that parse attacker-controlled SQL can terminate. Temporal Server exposes the affected parser through ListWorkers. When that API is enabled, an authenticated caller with namespace read permission can submit a malformed query that terminates the receiving Matching process. Repeated requests can sustain a denial of service. The issue affects availability only; no confidentiality or integrity impact was identified.

Impact

The vulnerability causes denial of service by crashing the Matching process in Temporal Server when parsing malformed SQL queries. It affects availability only. There is no known impact on confidentiality or integrity. Exploitation requires authentication with namespace read permission and the ListWorkers API to be enabled.

Summary

The temporalio/sqlparser component improperly validates array indices when parsing MySQL version comments. Specifically, the ExtractMysqlComment function uses the result of strings.IndexFunc without checking for a -1 return value, leading to out-of-bounds slice operations and a runtime panic in Go. This panic propagates unless recovered by the caller. Temporal Server exposes this parser via the ListWorkers API, which when enabled, allows authenticated users with namespace read permission to send malformed SQL queries that cause the Matching process to crash. This can be exploited repeatedly to sustain a denial of service condition. No confidentiality or integrity impacts are reported.

CWE-129Improper Validation of Array Index (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.
Architecture and Design · Input Validation
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overflow Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

CPE configurations (1)

Description

AI analysisMachine-generated, updated 21 Sep 2026, 12:02 UTC

WeaknessesCWE-129

Technical details

References

Community reviews

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