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NVD / CVE Program· CNA EEF

CVE-2026-53422: SFTP REALPATH path-existence oracle allowing filesystem enumeration outside configured root

Noroxi assessment

Priority: Monitor (action score 9/100)

  • 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: 0.26% (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 059e5785ef8c1d423820ca633fb7b37f47645172, 27.3.4.14, 28.5.0.3.

Low priority for now. Upgrade to Erlang OTP 059e5785ef8c1d423820ca633fb7b37f47645172, 27.3.4.14, 28.5.0.3 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

Observable Response Discrepancy vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated SFTP user to enumerate the existence of files and directories outside the configured root directory. The SSH_FXP_REALPATH handler in ssh_sftpd calls relate_file_name/3 with Canonicalize=false, unlike every other SFTP operation handler. This allows .. components in the requested path to bypass the is_within_root/2 check without being resolved. The un-canonicalized path then enters resolve_symlinks/2, which walks up the directory tree above the configured root and issues read_link() syscalls on arbitrary filesystem paths. An authenticated SFTP client can exploit this by sending a REALPATH request with a crafted traversal path. The server response differs depending on whether the target path exists on the host filesystem (SSH_FXP_NAME when the path resolves successfully, SSH_FX_NO_SUCH_FILE when it does not). This creates a path-existence oracle that an attacker can use to enumerate the filesystem structure outside the configured root, including the existence of sensitive files, directories, and mount points. The vulnerability leaks only the existence of paths. No file contents, credentials, or write access are obtainable through this issue alone. The information gained may assist further attacks when combined with other vulnerabilities. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routine ssh_sftpd:handle_op/4. This issue affects OTP from OTP 17.0 before OTP 29.0.3, OTP 28.5.0.3 and OTP 27.3.4.14, corresponding to ssh from 3.0.1 before 6.0.2, 5.5.2.2 and 5.2.11.9.

LowCVSS 2.3 · v4.0—No exploit Fix available
Published
Jul 2, 2026
Updated
Oct 25, 2026
EPSS
0.2% · 18th percentile

Report tools

JSON

Action score

9

Monitor

Low priority for now.

CVSS
9 / 40 · 2.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
2.3
NVD has not scored this yet; the score shown is the CNA’s.

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

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.

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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.

VendorProduct
erlangerlang/otp
erlangerlang/ssh

Affected versions

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 27.3.4.14
  • erlang erlang/otp28.0 and later · before 28.5.0.3
  • erlang erlang/otp29.0 and later · before 29.0.3
  • erlang erlang/ssh3.0.1 and later · before 5.2.11.9
  • erlang erlang/ssh5.3 and later · before 5.5.2.2
  • erlang erlang/ssh6.0 and later · before 6.0.2

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

    • 3.0.1 and lateraffected · otpfixed in 6.0.2, 5.5.2.2, 5.2.11.9
    • 17.0 and lateraffected · otpfixed in 29.0.3, 28.5.0.3, 27.3.4.14
    • 84adefa331c4159d432d22840663c38f155cd4c1 and lateraffected · gitfixed in 059e5785ef8c1d423820ca633fb7b37f47645172, 86622cfaacf57a02c7645d1999f946846b504c94, c5a8f50ae68888ff243c5c741a06d2b3a4b48b7a

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 1:29.0.3+dfsg-11:29.0.3+dfsg-1
openSUSE:Tumbleweederlangbefore 28.5.0.4-1.128.5.0.4-1.1
openSUSE:Tumbleweederlang27before 27.1.3-3.127.1.3-3.1
Red Hat:hummingbird:1erlang27before 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-asn1before 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-common_testbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-compilerbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-cryptobefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-debuggerbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-dialyzerbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-diameterbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-edocbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-eldapbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-erl_interfacebefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-ertsbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-etbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-eunitbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-examplesbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-ftpbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-gdb-toolsbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-inetsbefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1
Red Hat:hummingbird:1erlang27-jinterfacebefore 0:27.3.4.14-1.hum10:27.3.4.14-1.hum1

+22

Same product

erlang: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-55953TLS 1.2 and DTLS client accepts unoffered anonymous cipher suite, bypassing server authentication
    36Monitor
  • 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

Published before and after this one in the same product

  • ← EarlierCVE-2026-48859Jun 10, 2026 · SSH server timing side-channel in ssh_auth:check_password/3 allows unauthenticated username enumeration
    25Monitor
  • ← EarlierCVE-2026-48860Jun 10, 2026 · Distribution-over-TLS LAN allowlist silently bypassed due to sockname/peername confusion in inet_tls_dist
    30Monitor
  • Later →CVE-2026-54886Jul 2, 2026 · SSH SFTP server denial of service via extended channel data infinite loop
    21Monitor

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 OTP059e5785ef8c1d423820ca633fb7b37f47645172Vendor (CNA)
Erlang OTP27.3.4.14Vendor (CNA)
Erlang OTP28.5.0.3Vendor (CNA)
Erlang OTP29.0.3Vendor (CNA)
Erlang OTP5.2.11.9Vendor (CNA)
Erlang OTP5.5.2.2Vendor (CNA)
Erlang OTP6.0.2Vendor (CNA)
Erlang OTP86622cfaacf57a02c7645d1999f946846b504c94Vendor (CNA)
Erlang OTPc5a8f50ae68888ff243c5c741a06d2b3a4b48b7aVendor (CNA)
debian:erlang1:27.3.4.1+dfsg-1+deb13u3 · Debian:13Package registry (OSV)
opensuse:erlang28.5.0.4-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:erlang2727.1.3-3.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:erlang270:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-asn10:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-common_test0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-compiler0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-crypto0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-debugger0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-dialyzer0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-diameter0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-edoc0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-eldap0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-erl_interface0:27.3.4.14-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:erlang27-erts0:27.3.4.14-1.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.

No history yet (it accumulates with the daily EPSS job).

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.

No nightly-computed relations.

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-204 · Observable Response Discrepancy

CVSS vector

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

Change log

  1. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records