CVE-2026-68956 (GCVE-0-2026-68956)
Vulnerability from cvelistv5 – Published: 2026-09-22 08:49 – Updated: 2026-09-24 20:07
VLAI
EPSS
VEX
Title
SSH daemon allocates unbounded idle session channels, bypassing max_channels
Summary
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.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-22 10:12 UTC
CWE
- CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
References
8 references
Impacted products
3 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Erlang | OTP |
Affected:
18.1.2 , < *
(otp)
cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:* |
||
| Erlang | OTP |
Affected:
4.1.1 , < *
(otp)
cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:* |
||
| Erlang | OTP |
Affected:
84df3d4d0278e21a36a453bfee94799f0df67c2a , < *
(git)
Unaffected: 79c2d2be17d902c5f53969b5806b725efda831be , < * (git) Unaffected: e18100975f0e5a8d59d02de00df12247a91b443b , < * (git) Unaffected: e2bbad0107bba41491a4d549686fd023db8740da , < * (git) cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:* |
Date Public
2026-09-22 08:49
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"assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"assignerShortName": "EEF",
"cveId": "CVE-2026-68956",
"datePublished": "2026-09-22T08:49:21.760Z",
"dateReserved": "2026-08-17T13:30:02.155Z",
"dateUpdated": "2026-09-24T20:07:42.062Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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