CVE-2026-48686Patch(pavel-odintsov / fastnetmon)

LOWCVSS 9.8 · CRITICAL

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch pavel-odintsov fastnetmon systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

FastNetMon Community Edition through 1.2.9 contains a stack-based buffer overflow in the BGP NLRI (Network Layer Reachability Information) decoder. The function decode_bgp_subnet_encoding_ipv4_raw() in src/bgp_protocol.cpp reads prefix_bit_length directly from the BGP packet (line 99) without validating it is <= 32 for IPv4 prefixes. This value is passed to how_much_bytes_we_need_for_storing_certain_subnet_mask() which computes ceil(prefix_bit_length / 8), returning up to 32 bytes for a prefix_bit_length of 255. The result is used as the length argument to memcpy() (line 106), which copies into a 4-byte uint32_t stack variable (prefix_ipv4). This causes a stack buffer overflow of up to 28 bytes, which can be exploited for arbitrary code execution. Additionally, the unvalidated prefix_bit_length is passed to convert_cidr_to_binary_netmask_local_function_copy() (line 111), where a shift of (32 - cidr) with cidr > 32 causes undefined behavior.

0.5/ 10 priority

Sources & remediation

Weakness type (CWE)
CWE-120CWE-787

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • fastnetmon

Threat summary

  • Patch or workaround signal is available
  • 4 mentions across 3 observed days
  • Momentum state: stable

What's happening

  • Patch or workaround mentioned in 3 signals
  • Technical details provided in 4 signals
  • Disclosure: 1 classified signal
  • Peaked 2d ago at 2 mentions (2026-05-27); latest day: 1
  • 4 total mentions across 3 days

Affected systems

Products
fastnetmon

Deep dive

Activity timeline4 mentions / 3d
01122Mentions · 2026-05-27: 2Mentions · 2026-06-03: 1Mentions · 2026-07-29: 1Patch / Workaround · 2026-05-27: 1Patch / Workaround · 2026-06-03: 1Patch / Workaround · 2026-07-29: 1Technical Details · 2026-05-27: 2Technical Details · 2026-06-03: 1Technical Details · 2026-07-29: 105-2706-0307-29
Signal classification2 categories
Patch
375.0%
Disclosure
125.0%
Referenced assets19 URLs
By indicator
Classification over time
DateTotalLabels
2026-05-272
Disclosure1Patch1
2026-06-031
Patch1
2026-07-291
Patch1
Full discourse4 posts
  • Lorikeet Security@lorikeetsec
    Patch

    16 CVEs in FastNetMon Community Edition. All found, reported, and fixed. Our team ran a full source code audit of FastNetMon CE and surfaced 16 distinct vulnerabilities, now tracked as CVE-2026-48682 through CVE-2026-48697. First, credit where it is due. Huge thanks to Pavel Odintsov and the FastNetMon team. We sent the report and they moved immediately, confirmed the issues, staged fixes, and shipped patches in days. That is exactly how responsible disclosure is supposed to go, and a maintainer who turns it around that fast makes the whole ecosystem safer. The part I am most excited about: we did not find these by hand alone. Much of this audit ran on the same analysis engine we are building into Lory, our autonomous offensive security agent. The pattern that caught most of the worst bugs is simple to describe and brutal in practice, a length value read straight off the wire flowing into a memcpy with no bounds check. Teaching an agent to trace untrusted input from the network boundary to the dangerous sink is exactly what Lory is built to do at scale. FastNetMon was a real-world proving ground, and it delivered. The throughline on the critical ones: wire-controlled length, no validation, into a binary built with zero hardening flags. No stack canary, no FORTIFY, no PIE, no RELRO. That is what turns a parser bug into code execution as root on the box watching your network. If you run FastNetMon CE in production, update now. If you package it yourself, add hardening flags to your build. → All 16, with full technical writeups: Memory corruption CVE-2026-48682 · IPv4 parser OOB read https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48682-ipv4-parser-oob CVE-2026-48683 · NetFlow v9 data flowset OOB https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48683-netflow-v9-data-oob CVE-2026-48684 · NetFlow v9 options template OOB https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48684-netflow-v9-options-oob CVE-2026-48685 · BGP extended length misread https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48685-bgp-extended-length CVE-2026-48686 · BGP NLRI stack overflow (CVSS 9.8, RCE) https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48686-bgp-nlri-stack-overflow CVE-2026-48688 · BGP MP_REACH_NLRI IPv6 https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48688-bgp-mp-reach-nlri-ipv6 CVE-2026-48689 · Dynamic buffer off-by-one https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48689-dynamic-buffer-off-by-one CVE-2026-48690 · Packet storage integer overflow https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48690-packet-storage-integer-overflow CVE-2026-48691 · BGP AS_PATH overflow https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48691-bgp-as-path-overflow Injection CVE-2026-48687 · Juniper plugin command injection https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48687-juniper-cmd-injection CVE-2026-48694 · Juniper NETCONF injection https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48694-juniper-netconf-injection CVE-2026-48695 · MikroTik command injection https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48695-mikrotik-cmd-injection CVE-2026-48696 · ExaBGP sprintf overflow https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48696-exabgp-sprintf-overflow Auth & transport CVE-2026-48692 · Unauthenticated gRPC interface https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48692-grpc-no-auth CVE-2026-48693 · Symlink issue in temp handling https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48693-symlink-tmp CVE-2026-48697 · Missing TLS validation https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48697-missing-tls-validation → Read the C, find the line, prove the impact, disclose it right. #cybersecurity #infosec #vulnerabilityresearch #CVE #networksecurity #BGP #responsibledisclosure #AISecurity

    Post summary

    The post announces 16 CVEs discovered in FastNetMon CE, notes fast vendor patching, and urges users to apply the released fixes or hardening measures to mitigate diverse bugs ranging from OOB reads to command injections.

    00041338
    299 followersView on X
  • DFIR Lab@DFIR_Lab
    Patch

    🚨 CRITICAL: CVE-2026-48686 (CVSS 9.8) FastNetMon Community ≤1.2.9 stack buffer overflow in BGP NLRI decoder enables remote code execution. No auth required. Patch immediately. #CVE #Vulnerability #PatchNow #ThreatIntel https://t.co/RhWFU5VJeF

    Post summary

    The tweet announces the critical CVE-2026-48686, detailing a stack buffer overflow that allows remote code execution in FastNetMon v1.2.9 and calls for an immediate patch.

    0000036
    97 followersView on X
  • DailyCVE@dailycve
    Disclosure

    🔴 (FastNetMon Community Edition), Stack Buffer Overflow, #CVE-2026-48686 (critical) https://dailycve.com/fastnetmon-community-edition-stack-buffer-overflow-cve-2026-48686-critical/

    Post summary

    FastNetMon Community Edition has a critical stack buffer overflow (CVE‑2026‑48686). The post announces the vulnerability but does not provide a PoC, exploit code, patch, or evidence of active exploitation.

    0000045
    207 followersView on X
  • ADK Cyber@ADKCyber
    Patch

    Organizations running FastNetMon Community Edition should review CVE-2026-48686 (CVSS 9.8) and verify patch status for their deployments. https://nvd.nist.gov/vuln/detail/CVE-2026-48686 http://adkcyber.com via NVD Recent High CVSS #CyberSecurity #InfoSec #Vulnerability #AI #MachineLearning https://t.co/vxk2ybBBxv

    Post summary

    Security advisory urging FastNetMon Community Edition users to review the CVE-2026-48686 vulnerability (CVSS 9.8) and verify that patches are applied.

    0000037
    81 followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Apppavel-odintsovfastnetmon---

Explore more