CVE-2026-6985: Infinite Loop in Cesanta Mongoose
A weakness has been identified in Cesanta Mongoose up to 7.20. This vulnerability affects the function handle_opt of the file /src/net_builtin.c of the component TCP Option Handler. This manipulation of the argument optlen causes infinite loop. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 7.21 is able to resolve this issue. Upgrading the affected component is advised. VulDB has contacted the vendor early and they confirmed quickly, that this issue got fixed already.
AI Analysis
Technical Summary
This vulnerability affects the handle_opt function in the /src/net_builtin.c file of Cesanta Mongoose versions 7.0 through 7.20. Manipulating the optlen argument leads to an infinite loop, potentially causing a denial of service. The vulnerability is remotely exploitable without privileges or user interaction. The vendor has confirmed the fix is included in version 7.21. The CVSS 4.0 base score is 6.9 (medium severity), reflecting network attack vector, low complexity, no privileges required, no user interaction, and limited impact on availability.
Potential Impact
Successful exploitation results in an infinite loop condition that can cause denial of service by exhausting processing resources. There is no indication of code execution or data compromise. The vulnerability can be triggered remotely without authentication, making affected systems susceptible to disruption.
Mitigation Recommendations
Upgrade Cesanta Mongoose to version 7.21 or later, as this version contains the official fix for the vulnerability. Since the vendor has confirmed the issue is fixed, applying this update fully mitigates the risk. No additional mitigations are specified or required.
CVE-2026-6985: Infinite Loop in Cesanta Mongoose
Description
A weakness has been identified in Cesanta Mongoose up to 7.20. This vulnerability affects the function handle_opt of the file /src/net_builtin.c of the component TCP Option Handler. This manipulation of the argument optlen causes infinite loop. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 7.21 is able to resolve this issue. Upgrading the affected component is advised. VulDB has contacted the vendor early and they confirmed quickly, that this issue got fixed already.
CVSS v4.0
Score 6.9medium
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability affects the handle_opt function in the /src/net_builtin.c file of Cesanta Mongoose versions 7.0 through 7.20. Manipulating the optlen argument leads to an infinite loop, potentially causing a denial of service. The vulnerability is remotely exploitable without privileges or user interaction. The vendor has confirmed the fix is included in version 7.21. The CVSS 4.0 base score is 6.9 (medium severity), reflecting network attack vector, low complexity, no privileges required, no user interaction, and limited impact on availability.
Potential Impact
Successful exploitation results in an infinite loop condition that can cause denial of service by exhausting processing resources. There is no indication of code execution or data compromise. The vulnerability can be triggered remotely without authentication, making affected systems susceptible to disruption.
Mitigation Recommendations
Upgrade Cesanta Mongoose to version 7.21 or later, as this version contains the official fix for the vulnerability. Since the vendor has confirmed the issue is fixed, applying this update fully mitigates the risk. No additional mitigations are specified or required.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulDB
- Date Reserved
- 2026-04-24T19:12:47.755Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
- Epss Score
- 0.00042
- Epss Percentile
- 0.12716
- Epss Date
- 2026-04-26
- Gcve Source
- db.gcve.eu
Threat ID: 69ed416587115cfb684e5d6d
Added to database: 4/25/2026, 10:34:13 PM
Last enriched: 5/3/2026, 7:27:49 AM
Last updated: 6/10/2026, 5:40:21 PM
Views: 104
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