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PatchSiren cyber security CVE debrief

CVE-2026-48855 Erlang CVE debrief

CVE-2026-48855 is an Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Erlang OTP ssh (ssh_sftpd module) that allows File Discovery. The SSH_FXP_READLINK handler in ssh_sftpd sends the raw result of file:read_link/2 to the client without calling chroot_filename/2 to strip the backend root prefix. An authenticated SFTP client can create a symlink inside the chroot pointing to /; ssh_sftpd resolves the target to the absolute backend root and stores it on disk. Reading the symlink back via SSH_FXP_READLINK returns that absolute path, for example /data/sftp, instead of the chrooted value /. The information disclosed is the absolute filesystem path of the SFTP root directory and of any symlink targets within it. No file contents, credentials, or access to paths outside the root directory are obtainable through this issue alone.

Vendor
Erlang
Product
OTP
CVSS
LOW 2.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-10
Original CVE updated
2026-06-15
Advisory published
2026-06-10
Advisory updated
2026-06-15

Who should care

Users of Erlang OTP ssh (ssh_sftpd module) versions from OTP 17.0 before 29.0.2, 28.5.0.2 and 27.3.4.13 corresponding to ssh from 3.0.1 before 6.0.1, 5.5.2.1 and 5.2.11.8.

Technical summary

The vulnerability is caused by the SSH_FXP_READLINK handler in ssh_sftpd not calling chroot_filename/2 to strip the backend root prefix when sending the raw result of file:read_link/2 to the client. This allows an authenticated SFTP client to create a symlink inside the chroot pointing to /, which can be used to disclose the absolute filesystem path of the SFTP root directory and of any symlink targets within it.

Defensive priority

LOW

Recommended defensive actions

  • Update to OTP 29.0.2, 28.5.0.2 or 27.3.4.13 or later.
  • Use a version of ssh 6.0.1, 5.5.2.1 or 5.2.11.8 or later.

Evidence notes

The information disclosed is the absolute filesystem path of the SFTP root directory and of any symlink targets within it.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-48855 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-48855

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-48855 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-48855

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://cna.erlef.org/cves/CVE-2026-48855.html

    6b3ad84c-e1a6-4bf7-a703-f496b71e49db

  • Source reference

    Unverified legacy reference

    URL: https://github.com/erlang/otp/commit/8f4224a0d2676b0653d2c71a889a956e8c2c62d6

    6b3ad84c-e1a6-4bf7-a703-f496b71e49db

  • Source reference

    Unverified legacy reference

    URL: https://github.com/erlang/otp/security/advisories/GHSA-pv7g-pjrq-x2fh

    6b3ad84c-e1a6-4bf7-a703-f496b71e49db

  • Source reference

    Unverified legacy reference

    URL: https://osv.dev/vulnerability/EEF-CVE-2026-48855

    6b3ad84c-e1a6-4bf7-a703-f496b71e49db

  • Source reference

    Unverified legacy reference

    URL: https://www.erlang.org/doc/system/versions.html

    6b3ad84c-e1a6-4bf7-a703-f496b71e49db

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.