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TI-2026-85225 Aliases CVE-2026-115473

Out-of-bounds reads in Mongoose mg_path_is_sane path check

Priority HIGH 68CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · None · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

Cesanta Mongoose before 7.22 has an out-of-bounds read flaw in mg_path_is_sane in src/util.c, which reads path bytes beyond the path length when the path is only one or two bytes long (CWE-125). An unauthenticated remote attacker can send requests that reach mg_http_upload or mg_http_serve_dir with such short paths to trigger one-byte heap out-of-bounds reads. On bare-metal or RTOS targets without memory protection, the adjacent byte could be exposed or affect whether a path is accepted, and instrumented builds could crash.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

Mongoose is an embedded web server and network library. Prior to 7.22, mg_path_is_sane in src/util.c read path.buf[1] without first requiring path.len to be at least two and read s[2] when only two bytes remained. Unauthenticated remote requests reaching mg_http_upload or mg_http_serve_dir with the affected short path shapes could therefore trigger one-byte heap out-of-bounds reads. On bare-metal or RTOS targets without memory protection, the adjacent byte could be exposed or influence whether a path was accepted, and instrumented builds could crash. This issue is fixed in version 7.22.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00264 18th percentileScored 2026-11-07
Fix Fixed mongoose (cesanta): 7.22

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Cesantamongoosebefore 7.227.22Patch availableCNA
  • mongoose VendorCesanta Affected before 7.22 Fixed in 7.22 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:*——Cesanta
  • cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:* Versions — — ·Cesanta

Remediation

Upgrade Cesanta Mongoose to version 7.22, which fixes the issue.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA mongoose (cesanta) Fixed in 7.22

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-11-04 Threatist record created from CVE-2026-115473
  2. 2026-11-05 CISA SSVC decision points changed
  3. 2026-11-05 Priority changed: MEDIUM → HIGH
  4. 2026-11-06 Affected versions changed · Red Hat
  5. 2026-11-06 CVSS score added · Red Hat

References

Other 3

  • TI-2023-23198 Cesanta mjs v2.20.0 was discovered to contain a function pointer hijacking vulnerability… CVSS 3.1CRITICAL 9.8
  • TI-2026-51393 Mongoose: Content-Length + Transfer-Encoding coexistence enables request smuggling CVSS 3.1CRITICAL 9.1
  • TI-2018-15418 Mongoose Web Server 6.9 Denial of Service via Socket Connection CVSS 4.0HIGH 8.7
  • TI-2026-51389 Mongoose: TLS Hostname Verification Bypass via Overly Permissive Wildcard Matching CVSS 4.0CRITICAL 9.1
  • TI-2023-02723 Cesanta Mongoose MQTT Message Parsing Heap Overflow CVSS 3.1HIGH 8.8
  • TI-2020-15865 Buffer overflow in mg_resolve_from_hosts_file in Mongoose 6.18, when reading from a crafted hosts file. CVSS 3.1HIGH 8.8
See all 154 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences