CVE-2026-61343 - LibreBooking's email template editor save action passes the submitted template name directly into the destinat

CVE-2026-61343 + LibreBooking’s email template editor save action passes the submitted template name directly into the destinat + High + 2026-07-09

One-sentence business risk

The vulnerable component sits in a commonly deployed application path and can create a material breach, outage, or compliance risk.

Research notes

  • Root cause: LibreBooking’s email template editor save action passes the submitted template name directly into the destination file path, allowing a remote attacker with administrator credentials to write an arbitrary file outside the template directory and execute code.
  • Affected versions: LibreBooking LibreBooking: 0 to < 5.1.0.
  • Fixed / safe versions: 5.1.0.
  • Public exploit / PoC signal: the consulted NVD/GHSA/vendor sources describe the trigger class; treat it as reproducible until patched.
  • CVSS: 8.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N.

Exact vulnerable code pattern

curl --netrc "https://user@example.com/"  # URL username can select an unintended .netrc password

Fixed / mitigated code pattern

omit URL usernames when using .netrc, pin the host+login pair explicitly, and upgrade curl/libcurl to the fixed release

Dependency or runtime update:

rg -n "affected component|CVE-2026-61343" .
# update affected runtime/product to 5.1.0

Step-by-step integration guide

  1. Inventory affected component across source, lockfiles, SBOMs, container images, CI images, and deployment manifests.
  2. Upgrade to 5.1.0 or apply the exact vendor patch referenced below.
  3. Replace the vulnerable credential-leak pattern with the fixed pattern and fail closed on malformed input.
  4. Add a regression test that exercises the advisory trigger and proves the request is rejected, bounded, or authorized.
  5. Deploy through canary, monitor security logs and resource metrics, then remove temporary edge blocks only after all runtimes are fixed.

Alternative mitigations

  • Disable the vulnerable feature path while the package/runtime update rolls out.
  • Add WAF or reverse-proxy rules for traversal tokens, prototype-polluting keys, oversized frames, shell metacharacters, or unauthenticated tool calls matching the trigger class.
  • Restrict internal egress, rotate exposed secrets, and revoke affected tokens/keys if the vulnerability can disclose config, logs, JWT secrets, proxy credentials, or PKI material.
  • For admin/API authorization issues, temporarily require elevated roles and explicit ownership checks at the gateway.

Detection signature

id: cve-2026-61343-librebooking-s-email-template-editor-save-action
source: "MITRE CVE List V5"
dependency_or_product: "affected component"
affected: "LibreBooking LibreBooking: 0 to < 5.1.0"
fixed: "5.1.0"
signals:
  - "credential-leak"
  - "../"
  - "__proto__"
  - "tools/call"
  - "wp_ajax_nopriv"
  - "pickle.loads"
  - "shell command construction"
action: "upgrade, add regression test, and verify deploy artifact"

Copy-paste skill

You are remediating CVE-2026-61343 (LibreBooking's email template editor save action passes the submitted template name directly into the destinat) in this repository.

Find every affected dependency, runtime, image, service configuration, and reachable code path. Upgrade or patch to 5.1.0. Replace the vulnerable credential-leak pattern with a fail-closed implementation, add a regression test for the trigger shape, and update deployment/SBOM artifacts. If this repository does not control the affected runtime, create TRIAGE.md naming the owner, affected version, fixed version, and blocking decision.

Keywords, affected tech stack, and revenue tags

  • Keywords: CVE-2026-61343, credential-leak, affected component, MITRE CVE List V5.
  • Affected tech stack: general.
  • Revenue tags: sellable_to_fintech, enterprise_blocker, high_priority_sla.

References