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NVD / CVE Program· CNA EEF

CVE-2026-55953: TLS 1.2 and DTLS client accepts unoffered anonymous cipher suite, bypassing server authentication

CriticalCVSS 9.1 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 36/100)

  • 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: 0.23% (FIRST EPSS).
  • 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 064e236414614f9085cbbbd6eacf0e43c02d1b4b, 0a82596d425abe43dc2e0b3d74aa1557ef74051c, 11.2.12.11; azl3 erlang 26.2.5.21-4 on Azure Linux 3.0 26.2.5.21-3.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Erlang OTP 064e236414614f9085cbbbd6eacf0e43c02d1b4b, 0a82596d425abe43dc2e0b3d74aa1557ef74051c, 11.2.12.11; azl3 erlang 26.2.5.21-4 on Azure Linux 3.0 26.2.5.21-3 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

The Erlang/OTP ssl TLS 1.2 (and earlier) and DTLS client does not verify that the cipher suite selected by the server in ServerHello was among the suites offered by the client in ClientHello. The client-side tls_handshake:hello/5 handler validates the negotiated protocol version and the downgrade sentinel but hands the server-chosen suite directly to ssl_handshake:handle_server_hello_extensions/9, which installs it without a membership check. The TLS 1.3 client path performs this check (per RFC 8446), so it is not affected. An on-path attacker between the client and the intended server can respond with a ServerHello selecting an anonymous key exchange suite such as TLS_DH_anon_* or TLS_ECDH_anon_* that the client never offered. Anonymous suites do not require the server to present a certificate, so the entire verify_peer and cacerts configuration is bypassed: the attacker completes the handshake with its own ephemeral parameters, no certificate is validated, no hostname is checked, and ssl:connect returns {ok, Socket}. All subsequent application traffic is readable and modifiable by the attacker. 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 ssl from 5.3.4 before 11.2.12.11, from 11.3 before 11.6.0.4, and from 11.7 before 11.7.4. Whether OTP before OTP 17.0, corresponding to ssl before 5.3.4, is affected is unknown.

Published
Jul 27, 2026
Updated
Oct 24, 2026
EPSS
0.2% · 14th percentile

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
9.1
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:H/VI:H/VA:N/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.

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  • 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

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  • when exploit code appears or is weaponized
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  • 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.

VendorProduct
erlangerlang/otp
erlangerlang/ssl

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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 5.3.4unknown · otp
    • 5.3.4 and later · before 11.2.12.11affected · otp
    • 11.3 and later · before 11.6.0.4affected · otp
    • 11.7 and later · before 11.7.4affected · otp
    • 84adefa331c4159d432d22840663c38f155cd4c1 and lateraffected · gitfixed in 064e236414614f9085cbbbd6eacf0e43c02d1b4b, 0a82596d425abe43dc2e0b3d74aa1557ef74051c, e6ff938116b2872bccc478af7fefb56627285b77
Affected versions · NVD (6)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • erlang erlang/otp17.0 and later · before 27.3.4.15
  • erlang erlang/otp28.0 and later · before 28.5.0.4
  • erlang erlang/otp29.0 and later · before 29.0.4
  • erlang erlang/ssl5.3.4 and later · before 11.2.12.11
  • erlang erlang/ssl11.3 and later · before 11.6.0.4
  • erlang erlang/ssl11.7 and later · before 11.7.4

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+deb13u31:27.3.4.1+dfsg-1+deb13u3
Debian:14erlangbefore 1:29.0.4+dfsg-11:29.0.4+dfsg-1
openSUSE:Tumbleweederlang27before 27.1.3-3.127.1.3-3.1
Red Hat:hummingbird:1erlang27before 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-asn1before 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-common_testbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-compilerbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-cryptobefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-debuggerbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-dialyzerbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-diameterbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-edocbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-eldapbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-erl_interfacebefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-ertsbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-etbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-eunitbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-examplesbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-ftpbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-gdb-toolsbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-inetsbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-jinterfacebefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1
Red Hat:hummingbird:1erlang27-kernelbefore 0:27.3.4.15-0.1.hum10:27.3.4.15-0.1.hum1

+21

Same product

erlang: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-49759Stack buffer overflow in SCTP error cause parsing in inet_drv allows remote VM crash
    35Monitor
  • CVE-2026-59251Denial of service via exponential certificate policy tree growth in path validation
    34Monitor
  • CVE-2026-58227TLS/DTLS denial of service via unbounded recursion on cross-signed peer certificate chain
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-42792Jul 27, 2026 · epmd permanent DoS via EMFILE on accept(2) in erts
    25Monitor
  • ← EarlierCVE-2026-54890Jul 27, 2026 · BEAM VM crash via integer underflow in binary_to_term BIT_BINARY_EXT decoding
    32Monitor
  • ← EarlierCVE-2026-55737Jul 27, 2026 · Heap pointer corruption via signed/unsigned mismatch in LARGE_TUPLE_EXT decoding in erts external term format decoder
    20Monitor

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 OTP064e236414614f9085cbbbd6eacf0e43c02d1b4bVendor (CNA)
Erlang OTP0a82596d425abe43dc2e0b3d74aa1557ef74051cVendor (CNA)
Erlang OTP11.2.12.11Vendor (CNA)
Erlang OTP11.6.0.4Vendor (CNA)
Erlang OTP11.7.4Vendor (CNA)
Erlang OTP27.3.4.15Vendor (CNA)
Erlang OTP28.5.0.4Vendor (CNA)
Erlang OTP29.0.4Vendor (CNA)
Erlang OTPe6ff938116b2872bccc478af7fefb56627285b77Vendor (CNA)
azl3 erlang 26.2.5.21-4 on Azure Linux 3.026.2.5.21-3 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:erlang1:27.3.4.1+dfsg-1+deb13u3 · Debian:13Package registry (OSV)
opensuse:erlang2727.1.3-3.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:erlang270:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-asn10:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-common_test0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-compiler0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-crypto0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-debugger0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-dialyzer0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-diameter0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-edoc0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-eldap0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-erl_interface0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-erts0:27.3.4.15-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
suse:erlang23.3.4.19-150300.3.39.1 · SUSE:Linux Enterprise Module for Server Applications 15 SP7Package registry (OSV)
suse:erlang2626.2.1-150300.7.28.1 · SUSE:Linux Enterprise Module for Server Applications 15 SP7Package 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.

National notice (Türkiye Cybersecurity Directorate / USOM)

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

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-757 · Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')

CVSS vector

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

ATT&CK techniques

References

Show all references (6 more)

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

All records