CVE-2026-72703 (GCVE-0-2026-72703)
Vulnerability from cvelistv5 – Published: 2026-08-24 20:08 – Updated: 2026-08-24 20:08
VLAI
EPSS
VEX
Title
Rocq Prover 8.20 before 9.2.0 Guard Checker Accepts Non-Terminating Fixpoint via Unchecked Cross-Calls
Summary
The guard checker in Rocq Prover treats a parameter of a nested mutual fixpoint as uniform without examining calls between the different bodies of that fixpoint. find_uniform_parameters in kernel/inductive.ml inspects only self-recursive calls, so when no body calls itself the function concludes that every parameter is uniform. A parameter that grows through a cross-call from one body to another therefore keeps the subterm specification it inherited from the enclosing fixpoint, and a recursive call guarded by that specification is accepted although the argument is not structurally smaller. A non-terminating definition is admitted as structurally decreasing, which yields a term whose value equals its own successor and so a proof of False, from which any proposition follows. The proof requires no axioms, plugins or unsafe flags and Print Assumptions reports it as closed under the global context. Introduced in Coq 8.20 and fixed in Rocq 9.2.0.
Severity
6.3 (Medium)
CWE
- CWE-670 - Always-Incorrect Control Flow Implementation
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://github.com/rocq-prover/rocq | product |
| https://github.com/rocq-prover/rocq/issues/21682 | issue-tracking |
| https://github.com/rocq-prover/rocq/pull/21684 | issue-tracking |
| https://github.com/endrazine/rocq-cve-poc-21682 | exploit |
| https://www.vulncheck.com/advisories/rocq-prover-… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| rocq-prover | rocq |
Affected:
8.20 , < 9.2.0
(custom)
|
guessed |
Date Public
2026-02-28 00:00
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"url": "https://github.com/rocq-prover/rocq/pull/21684"
},
{
"tags": [
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"url": "https://github.com/endrazine/rocq-cve-poc-21682"
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"title": "Rocq Prover 8.20 before 9.2.0 Guard Checker Accepts Non-Terminating Fixpoint via Unchecked Cross-Calls",
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"vulnerability-lookup:meta": {
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"redhat_vex": {
"current_release_date": "2026-08-24T21:18:43+00:00",
"cve": "CVE-2026-72703",
"id": "CVE-2026-72703",
"initial_release_date": "2026-08-24T20:08:30.607000+00:00",
"product_status:known_not_affected": "1",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "rocq: Rocq Prover: Logical Flaw Allows Arbitrary Proof Generation via Unchecked Cross-Calls",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72703.json",
"version": "3"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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