PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-11586 curl CVE debrief

CVE-2026-11586 is a high-severity vulnerability in Curl, a popular command-line tool for transferring data. The vulnerability has a CVSS score of 7.5 and can be exploited by a malicious server to exhaust all available memory by flooding Curl with rapid, sequential PING messages. This vulnerability affects users of Curl, especially those who use it to transfer data over the internet. The vulnerability is caused by Curl's automatic response to WebSocket PING frames and its lack of an upper bound on memory allocation for unacknowledged frames.

Vendor
curl
Product
Unknown
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-03
Original CVE updated
2026-09-15
Advisory published
2026-07-03
Advisory updated
2026-09-15

Who should care

Users of Curl, especially those who use it to transfer data over the internet, should be aware of this vulnerability and take steps to mitigate it. This includes updating Curl to the latest version, implementing rate limiting on WebSocket PING frames, and monitoring system memory usage. Affected operators, platforms, and security teams should review the official CVE record and vendor advisories for more information.

Technical summary

By default, Curl automatically responds to WebSocket PING frames. However, Curl lacks an upper bound on memory allocation for unacknowledged frames, which can be exploited by a malicious server to exhaust all available memory by flooding Curl with rapid, sequential PING messages. This vulnerability can be mitigated by updating Curl to the latest version and implementing rate limiting on WebSocket PING frames.

Defensive priority

High

Recommended defensive actions

  • Update Curl to the latest version
  • Implement rate limiting on WebSocket PING frames
  • Monitor system memory usage
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-03T07:16:23.883Z and was last modified on 2026-07-07T17:59:46.920Z. The NVD entry is currently Analyzed. This information is based on the supplied source corpus and may not reflect the full scope of affected systems or potential impacts. Defenders should verify the affected scope and severity with the official CVE record and vendor advisories.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-11586 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-11586

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-11586 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-11586

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://curl.se/docs/CVE-2026-11586.html

    2499f714-1537-4658-8207-48ae4bb9eae9 - Patch, Vendor Advisory

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://curl.se/docs/CVE-2026-11586.json

    2499f714-1537-4658-8207-48ae4bb9eae9 - Vendor Advisory

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://hackerone.com/reports/3788931

    2499f714-1537-4658-8207-48ae4bb9eae9 - Exploit, Issue Tracking, Third Party Advisory

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.