# CVE-2026-116780: FreeSWITCH: Heap out-of-bounds read in FreeSWITCH core variable expansion via `${variable:offset}` slicing

Status: published. Published: 2026-11-05. Updated: 2026-11-09.

FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hardware. Prior to 1.11.2, switch_event_expand_headers_check() advanced beyond its heap copy when a positive offset in ${variable:offset} exceeded the variable value's length. The following length calculation and copy appended adjacent heap memory to the expansion result, potentially exposing channel variables, credentials, allocator data, and pointer bytes. The flaw is reachable through configuration templates that slice remote input and through authenticated Event Socket eval or Event Socket expand commands; the separate channel-variable expander used by ordinary dialplan slicing is unaffected. The requester cannot choose adjacent memory and disclosure stops at a zero byte, but repeated expansion can influence the layout. This issue is fixed in version 1.11.2.

## Remediation

- fix: FreeSWITCH (c): GitHub reports patched versions >= 1.11.2. Check the advisory for the affected release branch. (source: GitHub GHSA-2p6g-9c8q-232p) — https://github.com/signalwire/freeswitch/security/advisories/GHSA-2p6g-9c8q-232p

## Affected products and versions

- signalwire / freeswitch: < 1.11.2 (affected). Source: CNA: GitHub_M
-  / FreeSWITCH (FreeSWITCH): <= 1.11.1 (affected, GitHub advisory range). Source: GitHub GHSA-2p6g-9c8q-232p

## Severity and prioritization

- CVSS 3.1: 2.7 (low); CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N; source: CNA: GitHub_M

- CVSS 3.1: 2.7 (low); CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.22% as of 2026-11-09; percentile 13.29%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-125, CWE-200

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/signalwire/freeswitch/security/advisories/GHSA-2p6g-9c8q-232p (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/signalwire/freeswitch/commit/30cdb387ae0fac0cbbeb6ac05416aaffb9252258 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/signalwire/freeswitch/releases/tag/v1.11.2 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/signalwire/freeswitch/commit/30cdb387ae0fac0cbbeb6ac05416aaffb9252258 (security-advisories@github.com)

- https://github.com/signalwire/freeswitch/releases/tag/v1.11.2 (security-advisories@github.com)

- https://github.com/signalwire/freeswitch/security/advisories/GHSA-2p6g-9c8q-232p (security-advisories@github.com)

- https://github.com/signalwire/freeswitch/security/advisories/GHSA-2p6g-9c8q-232p (GitHub Security Advisories; advisory)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-116780; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116780; retrieved 2026-11-06; source updated 2026-11-05

- GitHub Security Advisories: https://github.com/signalwire/freeswitch/security/advisories/GHSA-2p6g-9c8q-232p; retrieved 2026-11-07; source updated 2026-10-28

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-116780; retrieved 2026-11-09; source updated Not reported

Revision: 119c8dbf935da583276ab354a58865ff46561cdb290978a2ab33dc74cc9fd2f3

Canonical: https://y2.dev/cve/CVE-2026-116780

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.