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NVD / CVE Program· CNA EEF

CVE-2026-68956: SSH daemon allocates unbounded idle session channels, bypassing max_channels

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.37% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Erlang OTP 27.3.4.18, 28.5.0.7, 29.1.1; azl3 erlang 26.2.5.21-6 on Azure Linux 3.0 26.2.5.21-7.

Low priority for now. Upgrade to Erlang OTP 27.3.4.18, 28.5.0.7, 29.1.1; azl3 erlang 26.2.5.21-6 on Azure Linux 3.0 26.2.5.21-7 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

Allocation of Resources Without Limits or Throttling vulnerability in Erlang/OTP ssh allows an authenticated remote attacker to exhaust node memory by repeatedly opening session channels that are never assigned a handler. The "session" clause of ssh_connection:handle_msg/4 checks only minimal_remote_max_packet_size before calling setup_session/5, which unconditionally builds a #channel{} record and stores it in the ETS channel cache. The max_channels daemon option is consulted only by ssh_channel_sup:max_num_channels_not_exceeded/2, which counts supervisor children, so a channel that never gets a shell, exec, or subsystem handler is invisible to the limit and setting the option to a finite value does not mitigate the attack. RFC 4254 section 5.1 permits many session channels per connection, and each record costs only a few hundred bytes, so a single authenticated connection can accumulate channels until the node runs out of memory and the emulator terminates, affecting every application on it. No file contents, credentials, or write access are obtainable. This issue affects OTP from OTP 18.1.2 before OTP 27.3.4.18, OTP 28.5.0.7, and OTP 29.1.1, corresponding to ssh from 4.1.1 before 5.2.11.13, 5.5.2.6, and 6.0.6. Whether OTP before OTP 18.1.2, corresponding to ssh before 4.1.1, is affected is unknown.

HighCVSS 7.1 · v4.0—No exploit Fix available
Published
Sep 22, 2026
Updated
Sep 24, 2026
EPSS
0.3% · 32th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
7.1
NVD has not scored this yet; the score shown is the CNA’s.

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

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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

    • 18.1.2 and lateraffected · otpfixed in 27.3.4.18, 28.5.0.7, 29.1.1
    • 4.1.1 and lateraffected · otpfixed in 5.2.11.13, 5.5.2.6, 6.0.6
    • 84df3d4d0278e21a36a453bfee94799f0df67c2a and lateraffected · gitfixed in 79c2d2be17d902c5f53969b5806b725efda831be, e18100975f0e5a8d59d02de00df12247a91b443b, e2bbad0107bba41491a4d549686fd023db8740da
    • 79c2d2be17d902c5f53969b5806b725efda831be and laternot affected · git
    • e18100975f0e5a8d59d02de00df12247a91b443b and laternot affected · git
    • e2bbad0107bba41491a4d549686fd023db8740da and laternot affected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12erlangfrom 0—
Debian:13erlangbefore 1:27.3.4.1+dfsg-1+deb13u41:27.3.4.1+dfsg-1+deb13u4
Debian:14erlangbefore 1:29.1.1+dfsg-11:29.1.1+dfsg-1

Same product

erlang: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-89422TLS 1.3 client skips server authentication when ServerHello carries an unsolicited pre_shared_key extension
    37Monitor
  • CVE-2026-74835inets,httpd: Memory Exhaustion via Unenforced max_body_size During Chunked Body Reception
    34Monitor
  • CVE-2026-71380httpd applies no timeout while receiving a request body, parking a worker on a stalled client
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-75538Sep 1, 2026 · A Signed Length Overflow in Erlang/OTP's inet TCP Driver Overflows the Receive Buffer Into BEAM VM Memory From an Unauthenticated Peer
    32Monitor
  • ← EarlierCVE-2026-65634Sep 22, 2026 · Superlinear CPU denial of service in Erlang/OTP ASN.1 OBJECT IDENTIFIER decoder
    32Monitor
  • Later →CVE-2026-105236Oct 14, 2026 · TLS 1.2 session resumption in ssl crosses SNI virtual-host client-certificate trust boundaries
    25Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
Erlang OTP27.3.4.18Vendor (CNA)
Erlang OTP28.5.0.7Vendor (CNA)
Erlang OTP29.1.1Vendor (CNA)
Erlang OTP5.2.11.13Vendor (CNA)
Erlang OTP5.5.2.6Vendor (CNA)
Erlang OTP6.0.6Vendor (CNA)
Erlang OTP79c2d2be17d902c5f53969b5806b725efda831beVendor (CNA)
Erlang OTPe18100975f0e5a8d59d02de00df12247a91b443bVendor (CNA)
Erlang OTPe2bbad0107bba41491a4d549686fd023db8740daVendor (CNA)
azl3 erlang 26.2.5.21-6 on Azure Linux 3.026.2.5.21-7 · Release NotesMicrosoft (MSRC)
debian:erlang1:27.3.4.1+dfsg-1+deb13u4 · Debian:13Package registry (OSV)
debian:erlang1:29.1.1+dfsg-1 · Debian:14Package 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.

Credits

All researchers

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

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-7039921 days aparthttpd does not enforce the documented default max_clients connection limit
    34Monitor
  • CVE-2026-7483521 days apartinets,httpd: Memory Exhaustion via Unenforced max_body_size During Chunked Body Reception
    34Monitor
  • CVE-2026-5595121 days aparthttpc memory exhaustion via unbounded response header accumulation
    32Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • 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
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-770 · Allocation of Resources Without Limits or Throttling

CVSS vector

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

Attack context

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

Change log

  1. Fix✗ → ✓

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References

Show all references (7 more)

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

All records