{"id":"CVE-2026-48855","state":"PUBLISHED","title":"SFTP READLINK Leaks Absolute Backend Filesystem Path When Root Is Configured","description":"Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Erlang OTP ssh (ssh_sftpd module) allows File Discovery.\n\nThe 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 /.\n\nThe 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.\n\nThis vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl.\n\nThis issue affects OTP from OTP 17.0 before OTP 27.3.4.13, OTP 28.5.0.2, and OTP 29.0.2, corresponding to ssh from 3.0.1 before 5.2.11.8, 5.5.2.1, and 6.0.1. Whether OTP before OTP 17.0, corresponding to ssh before 3.0.1, is affected is unknown.","publishedAt":"2026-06-10T14:35:49.683Z","updatedAt":"2026-09-24T20:35:33.970Z","severity":{"score":2.3,"label":"Low","version":"4.0","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","source":"EEF"},"assigner":"EEF","products":["Erlang OTP"],"affected":[{"vendor":"Erlang","product":"OTP","packageName":"otp","packageURL":"pkg:software-id/erlang.org/otp","defaultStatus":"unknown","versions":[{"version":"17.0","status":"affected","lessThan":"*","changes":[{"at":"27.3.4.13","status":"unaffected"},{"at":"28.5.0.2","status":"unaffected"},{"at":"29.0.2","status":"unaffected"}],"versionType":"otp"}],"cpes":["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"],"modules":["ssh_sftpd"],"programFiles":["lib/ssh/src/ssh_sftpd.erl"],"programRoutines":[{"name":"ssh_sftpd:handle_op/4"}]},{"vendor":"Erlang","product":"OTP","packageName":"ssh","packageURL":"pkg:otp/ssh?repository_url=https:%2F%2Fgithub.com%2Ferlang%2Fotp&vcs_url=git%2Bhttps:%2F%2Fgithub.com%2Ferlang%2Fotp.git","defaultStatus":"unknown","versions":[{"version":"3.0.1","status":"affected","lessThan":"*","changes":[{"at":"5.2.11.8","status":"unaffected"},{"at":"5.5.2.1","status":"unaffected"},{"at":"6.0.1","status":"unaffected"}],"versionType":"otp"}],"cpes":["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"],"modules":["ssh_sftpd"],"programFiles":["src/ssh_sftpd.erl"],"programRoutines":[{"name":"ssh_sftpd:handle_op/4"}],"repo":"https://github.com/erlang/otp"},{"vendor":"Erlang","product":"OTP","packageName":"erlang/otp","packageURL":"pkg:github/erlang/otp","defaultStatus":"unknown","versions":[{"version":"08225797f7ef943d0c82a1d9dd6650d94ca2580d","status":"affected","lessThan":"8f4224a0d2676b0653d2c71a889a956e8c2c62d6","versionType":"git"},{"version":"8f4224a0d2676b0653d2c71a889a956e8c2c62d6","status":"unaffected","lessThan":"*","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"],"modules":["ssh_sftpd"],"programFiles":["lib/ssh/src/ssh_sftpd.erl"],"programRoutines":[{"name":"ssh_sftpd:handle_op/4"}],"repo":"https://github.com/erlang/otp"}],"references":["https://github.com/erlang/otp/security/advisories/GHSA-pv7g-pjrq-x2fh","https://cna.erlef.org/cves/CVE-2026-48855.html","https://osv.dev/vulnerability/EEF-CVE-2026-48855","https://www.erlang.org/doc/system/versions.html#order-of-versions","https://github.com/erlang/otp/commit/08225797f7ef943d0c82a1d9dd6650d94ca2580d","https://github.com/erlang/otp/commit/8f4224a0d2676b0653d2c71a889a956e8c2c62d6"],"weaknesses":["CWE-200"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/48xxx/CVE-2026-48855.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-48855","state":"PUBLISHED","datePublished":"2026-06-10T14:35:49.683Z","dateUpdated":"2026-09-24T20:35:33.970Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-05-25T20:44:10.697Z"},"containers":{"cna":{"title":"SFTP READLINK Leaks Absolute Backend Filesystem Path When Root Is Configured","descriptions":[{"lang":"en","value":"Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Erlang OTP ssh (ssh_sftpd module) allows File Discovery.\n\nThe 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 /.\n\nThe 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.\n\nThis vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl.\n\nThis issue affects OTP from OTP 17.0 before OTP 27.3.4.13, OTP 28.5.0.2, and OTP 29.0.2, corresponding to ssh from 3.0.1 before 5.2.11.8, 5.5.2.1, and 6.0.1. Whether OTP before OTP 17.0, corresponding to ssh before 3.0.1, is affected is unknown."}],"affected":[{"vendor":"Erlang","product":"OTP","packageName":"otp","packageURL":"pkg:software-id/erlang.org/otp","defaultStatus":"unknown","versions":[{"version":"17.0","status":"affected","lessThan":"*","changes":[{"at":"27.3.4.13","status":"unaffected"},{"at":"28.5.0.2","status":"unaffected"},{"at":"29.0.2","status":"unaffected"}],"versionType":"otp"}],"cpes":["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"],"modules":["ssh_sftpd"],"programFiles":["lib/ssh/src/ssh_sftpd.erl"],"programRoutines":[{"name":"ssh_sftpd:handle_op/4"}]},{"vendor":"Erlang","product":"OTP","packageName":"ssh","packageURL":"pkg:otp/ssh?repository_url=https:%2F%2Fgithub.com%2Ferlang%2Fotp&vcs_url=git%2Bhttps:%2F%2Fgithub.com%2Ferlang%2Fotp.git","defaultStatus":"unknown","versions":[{"version":"3.0.1","status":"affected","lessThan":"*","changes":[{"at":"5.2.11.8","status":"unaffected"},{"at":"5.5.2.1","status":"unaffected"},{"at":"6.0.1","status":"unaffected"}],"versionType":"otp"}],"cpes":["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"],"modules":["ssh_sftpd"],"programFiles":["src/ssh_sftpd.erl"],"programRoutines":[{"name":"ssh_sftpd:handle_op/4"}],"repo":"https://github.com/erlang/otp"},{"vendor":"Erlang","product":"OTP","packageName":"erlang/otp","packageURL":"pkg:github/erlang/otp","defaultStatus":"unknown","versions":[{"version":"08225797f7ef943d0c82a1d9dd6650d94ca2580d","status":"affected","lessThan":"8f4224a0d2676b0653d2c71a889a956e8c2c62d6","versionType":"git"},{"version":"8f4224a0d2676b0653d2c71a889a956e8c2c62d6","status":"unaffected","lessThan":"*","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"],"modules":["ssh_sftpd"],"programFiles":["lib/ssh/src/ssh_sftpd.erl"],"programRoutines":[{"name":"ssh_sftpd:handle_op/4"}],"repo":"https://github.com/erlang/otp"}],"references":[{"url":"https://github.com/erlang/otp/security/advisories/GHSA-pv7g-pjrq-x2fh","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-48855.html","name":"EEF CNA record for CVE-2026-48855","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-48855","name":"OSV record EEF-CVE-2026-48855","tags":["related"]},{"url":"https://www.erlang.org/doc/system/versions.html#order-of-versions","name":"Erlang/OTP version ordering","tags":["x_version-scheme"]},{"url":"https://github.com/erlang/otp/commit/08225797f7ef943d0c82a1d9dd6650d94ca2580d","name":"Introducing commit 0822579 in erlang/otp","tags":["related"]},{"url":"https://github.com/erlang/otp/commit/8f4224a0d2676b0653d2c71a889a956e8c2c62d6","name":"Fix commit 8f4224a in erlang/otp","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":2.3,"baseSeverity":"LOW","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-200","description":"CWE-200 Exposure of Sensitive Information to an Unauthorized Actor","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-09-24T20:35:33.970Z"},"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"
The SFTP subsystem must be enabled on the SSH server and the root option must be configured in the ssh_sftpd:subsystem_spec/1 call. Deployments without the root option are not affected.
"},{"base64":false,"type":"text/markdown","value":"The SFTP subsystem must be enabled on the SSH server and the `root` option must be configured in the `ssh_sftpd:subsystem_spec/1` call. Deployments without the `root` option are not affected."}],"value":"The SFTP subsystem must be enabled on the SSH server and the root option must be configured in the ssh_sftpd:subsystem_spec/1 call. Deployments without the root option are not affected."}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*","versionEndExcluding":"27.3.4.13","vulnerable":true},{"criteria":"cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*","versionEndExcluding":"28.5.0.2","versionStartIncluding":"28.0","vulnerable":true},{"criteria":"cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*","versionEndExcluding":"29.0.2","versionStartIncluding":"29.0","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"finder","value":"Jonatan Männchen / EEF"},{"lang":"en","type":"remediation developer","value":"Jonatan Männchen / EEF"},{"lang":"en","type":"remediation developer","value":"Michał Wąsowski"},{"lang":"en","type":"remediation reviewer","value":"Jakub Witczak"}],"datePublic":"2026-06-10T14:35:49.000Z","impacts":[{"capecId":"CAPEC-116","descriptions":[{"lang":"en","value":"CAPEC-116 Excavation"}]}],"source":{"discovery":"INTERNAL"},"workarounds":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"
\n
Use OS-level chroot to run the Erlang VM/SFTP server process in an isolated filesystem environment, eliminating reliance on the application-level root option.
\n
Ensure that the SFTP server port is not reachable from untrusted machines.
\n
Ensure that no sensitive information (usernames, project names, mount topology) is inferrable from the absolute path of the configured root directory.
\n
"},{"base64":false,"type":"text/markdown","value":"* Use OS-level chroot to run the Erlang VM/SFTP server process in an isolated filesystem environment, eliminating reliance on the application-level `root` option.\n* Ensure that the SFTP server port is not reachable from untrusted machines.\n* Ensure that no sensitive information (usernames, project names, mount topology) is inferrable from the absolute path of the configured root directory."}],"value":"* Use OS-level chroot to run the Erlang VM/SFTP server process in an isolated filesystem environment, eliminating reliance on the application-level root option.\n* Ensure that the SFTP server port is not reachable from untrusted machines.\n* Ensure that no sensitive information (usernames, project names, mount topology) is inferrable from the absolute path of the configured root directory."}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-10T16:22:16.684743Z","id":"CVE-2026-48855","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-10T16:22:24.746Z"}}]}}}