CVE-2026-77938 json
Letta through 0.16.8 Credential Exposure via Tool Sandbox Environment Inheritance
published 2026-10-20 20 d ago modified 2026-10-20 19 d ago also EUVD-2026-104694
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 36%
- public exploits
- 0
- none known
Summary
Letta through 0.16.8 contains an information disclosure vulnerability that allows users running tools to read server secrets because LocalSandbox subprocesses inherit the full server environment. Attackers can run code via POST /v1/tools/run or custom tools to read LETTA_PG_URI, POSTGRES_PASSWORD, and provider API keys, then access cross-tenant database data.
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 19 d ago
Exploit prediction
0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- lasso.security https://www.lasso.security/vulnerability-database/cve-2026-77938 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 7.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N |
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
| CNA | 4.0 | 7.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- letta-ai letta
Classification
- Weakness
-
- CWE-526 Cleartext Storage of Sensitive Information in an Environment Variable
References
-
lasso.security
/vulnerability-database/cve-2026-77938
technical-description, exploit
-
github.com
/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/letta/services/tool_sandbox/base.py#L487
technical-description
-
vulncheck.com
/advisories/letta-through-0.16.8-credential-exposure-via-tool-sandbox-environment-inheritance
third-party-advisory
Sources
- CVE List CVE-2026-77938
- NVD CVE-2026-77938
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.