Cyber Resilience

CVE-2026-48685

Pavel-Odintsov Fastnetmon ≤ 1.2.9

Published
26 May 2026
Modified
24 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0029 22th percentile
Risk Priority 49 floored blend · peak EPSS

Summary

CVE-2026-48685 is a medium-severity Improper Handling of Length Parameter Inconsistency (CWE-130) vulnerability in Pavel-Odintsov Fastnetmon. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 22th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then…

more

reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.

CWE(s)
CWE-130

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-48691Same product: Pavel-Odintsov Fastnetmon
CVE-2026-48690Same product: Pavel-Odintsov Fastnetmon
CVE-2026-48696Same product: Pavel-Odintsov Fastnetmon
CVE-2026-48684Same product: Pavel-Odintsov Fastnetmon
CVE-2026-48688Same product: Pavel-Odintsov Fastnetmon
CVE-2026-48689Same product: Pavel-Odintsov Fastnetmon
CVE-2026-48686Same product: Pavel-Odintsov Fastnetmon
CVE-2026-48694Same product: Pavel-Odintsov Fastnetmon
CVE-2024-56072Same product: Pavel-Odintsov Fastnetmon
CVE-2026-48692Same product: Pavel-Odintsov Fastnetmon

Affected Assets

pavel-odintsov
fastnetmon
≤ 1.2.9

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V3.5.5
  • V4.2.1
  • V4.2.2

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover length-parameter inconsistencies through targeted parsing tests.

SI-10 Information Input Validation good match

Input validation enforces correct length-to-data consistency checks on parsed messages before processing.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly enforce length validation and input sanitization during coding and review.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect length-inconsistency vulnerabilities before deployment.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and length checks that directly address inconsistent length fields.

A.8.26 Application security requirements partial match
prevents

Application security requirements include explicit rules for handling message lengths and data structures.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles require robust parsing and bounds checking to prevent length-related flaws.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prohibit improper length handling and enforce defensive parsing practices.

References