NVD / CVE Program· CNA EEF

CVE-2026-59250: Megaco flex scanner buffer overflow via oversized property parm name

HighCVSS 8.3 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 33/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.77% (FIRST EPSS); higher than 56.3% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Erlang OTP 27.3.4.15, 28.5.0.4, 29.0.4; azl3 erlang 26.2.5.21-4 on Azure Linux 3.0 26.2.5.21-5.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Erlang OTP 27.3.4.15, 28.5.0.4, 29.0.4; azl3 erlang 26.2.5.21-4 on Azure Linux 3.0 26.2.5.21-5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Classic buffer overflow in the Erlang/OTP megaco flex scanner C driver allows a remote unauthenticated attacker to corrupt the driver's memory (and potentially achieve remote code execution or a denial-of-service crash) by sending a single text-encoded H.248/Megaco message containing an oversized property parm name. When tokenizing a Local/Remote descriptor, mfs_load_property_groups extracts the attacker-controlled property name (bounded only by the message length) and, when no value follows, formats it into a fixed 512-byte error_msg field of the MfsErlDrvData struct using an unchecked sprintf call. Names longer than roughly 452 bytes overflow into the immediately following struct fields (text_buf, text_ptr, term_spec, term_spec_size, term_spec_index), overwriting live pointers and counters with attacker-chosen bytes. Subsequent scanner code writes and frees through the corrupted pointers, producing arbitrary write and arbitrary free primitives inside the BEAM VM process, which can be leveraged for remote code execution. On builds compiled with _FORTIFY_SOURCE the overflow is detected at runtime and terminates the process with SIGABRT, resulting in denial of service. The overflow occurs in the flex scanner before any grammar or Megaco-level authentication processing, so exploitation requires only network reachability to the megaco transport port on a node configured with {scanner, flex}. This vulnerability is associated with program files lib/megaco/src/flex/megaco_flex_scanner_drv.flex.src and program routines mfs_load_property_groups. This issue affects OTP from OTP 17.0 before OTP 27.3.4.15, from OTP 28.0 before OTP 28.5.0.4, and from OTP 29.0 before OTP 29.0.4, corresponding to megaco from 3.17.1 before 4.7.2.2, from 4.8 before 4.8.3.1, and from 4.9 before 4.9.1. Whether OTP before OTP 17.0, corresponding to megaco before 3.17.1, is affected is unknown.

Published: Jul 27, 2026
Updated: Oct 24, 2026
EPSS: 0.7% · 56th percentile
CWE: CWE-120

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 33 / 40 · 8.3 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.7%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · EEF: 8.3; NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.

Erlang OTP
- before 17.0unknown · otp
- 17.0 and later · before 27.3.4.15affected · otp
- 28.0 and later · before 28.5.0.4affected · otp
- 29.0 and later · before 29.0.4affected · otp
- before 3.17.1unknown · otp
- 3.17.1 and later · before 4.7.2.2affected · otp
- 4.8 and later · before 4.8.3.1affected · otp
- 4.9 and later · before 4.9.1affected · otp
- 84adefa331c4159d432d22840663c38f155cd4c1 and later · before 8704c8f550a11ed5f825e3c011ecb03565b79c4faffected · git

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	erlang	from 0	—
Debian:13	erlang	before 1:27.3.4.1+dfsg-1+deb13u3	1:27.3.4.1+dfsg-1+deb13u3
Debian:14	erlang	before 1:29.0.4+dfsg-1	1:29.0.4+dfsg-1
openSUSE:Tumbleweed	erlang27	before 27.1.3-3.1	27.1.3-3.1
Red Hat:hummingbird:1	erlang27	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-asn1	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-common_test	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-compiler	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-crypto	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-debugger	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-dialyzer	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-diameter	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-edoc	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-eldap	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-erl_interface	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-erts	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-et	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-eunit	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-examples	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-ftp	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-gdb-tools	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-inets	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-jinterface	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1	erlang27-kernel	before 0:27.3.4.15-0.1.hum1	0:27.3.4.15-0.1.hum1

+20

Same product

erlang: all records

Other highest-scoring records for the same primary product.

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Published before and after this one in the same product

← EarlierCVE-2026-21620Feb 20, 2026 · Relative Path Traversal, Improper Isolation or Compartmentalization vulnerability in erlang otp erlang/otp (tftp_file modules), erlang otp…
9Monitor
← EarlierCVE-2026-47078Jul 27, 2026 · Relative path traversal in zip:unzip/zip:extract via check_dir_level depth-counter bypass
19Monitor
Later →CVE-2026-55951Sep 1, 2026 · httpc memory exhaustion via unbounded response header accumulation
32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Erlang OTP	27.3.4.15	Vendor (CNA)
Erlang OTP	28.5.0.4	Vendor (CNA)
Erlang OTP	29.0.4	Vendor (CNA)
Erlang OTP	4.7.2.2	Vendor (CNA)
Erlang OTP	4.8.3.1	Vendor (CNA)
Erlang OTP	4.9.1	Vendor (CNA)
Erlang OTP	8704c8f550a11ed5f825e3c011ecb03565b79c4f	Vendor (CNA)
azl3 erlang 26.2.5.21-4 on Azure Linux 3.0	26.2.5.21-5 · CBL-Mariner Releases	Microsoft (MSRC)
debian:erlang	1:27.3.4.1+dfsg-1+deb13u3 · Debian:13	Package registry (OSV)
opensuse:erlang27	27.1.3-3.1 · openSUSE:Tumbleweed	Package registry (OSV)
red hat:erlang27	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-asn1	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-common_test	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-compiler	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-crypto	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-debugger	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-dialyzer	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-diameter	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-edoc	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-eldap	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-erl_interface	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
red hat:erlang27-erts	0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1	Package registry (OSV)
suse:erlang	23.3.4.19-150300.3.39.1 · SUSE:Linux Enterprise Module for Server Applications 15 SP7	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

erlang/otpcommit 8704c8f

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Jakub Witczakremediation developer
Micael Karlbergremediation reviewer
Jonatan Männchen / EEFfinder

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-0662 · Jul 28, 2026(Erlang/OTP Güvenlik Zafiyeti)

All national notices →

Not on record for this CVE: variant or chain candidate · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: X

Weakness class (CWE)

CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/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

nvd-secondary

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

The bug in code

The whole CWE-120 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1char buf[256];
2memcpy(buf, pkt->data, pkt->len);

Fixed

1char buf[256];
2if (pkt->len > sizeof(buf)) {
3  return -EINVAL;
4}
5memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log (1)

Fix✗ → ✓Sep 28, 2026, 10:11 PM UTC

For records you follow, these changes also arrive as notifications. →

References

cna.erlef.org/cves/CVE-2026-59250.html

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records