CVE-2026-112265
LangBot through 4.11.0 contains a missing authenticity verification vulnerability that allows unauthenticated attackers to inject forged Lark/Feishu events by skipping signature checks.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.15%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
LangBot through 4.11.0 contains a missing authenticity verification vulnerability that allows unauthenticated attackers to inject forged Lark/Feishu events by skipping signature checks. Attackers knowing a bot UUID can POST fabricated im.message.receive_v1 or card.action.trigger events to drive the LLM pipeline, tools, and approvals as other users.
- CVSS 4.0
- 8.3 HIGHCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.15% probability · 4th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-345
- Source
- disclosure@vulncheck.com
EPSS moved from 0.2% on 20 October 2026 to 0.2% on 26 October 2026.
References
- https://github.com/langbot-app/LangBot/blob/v4.11.0/src/langbot/pkg/api/http/controller/groups/webhooks.py
- https://github.com/langbot-app/LangBot/blob/v4.11.0/src/langbot/pkg/platform/adapters/lark/adapter.py
- https://github.com/langbot-app/LangBot/blob/v4.11.0/src/langbot/pkg/platform/sources/lark.py
- https://github.com/langbot-app/LangBot/commit/43c481d74a6388657b84baa7d292c613c75c24f9
- https://github.com/langbot-app/LangBot/issues/2627
- https://www.vulncheck.com/advisories/langbot-through-4.11.0-missing-lark-feishu-webhook-authenticity-verification
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.