In CUPS versions 2.4.16 and prior, the RSS notifier allows path traversal in notify-recipient-uri (e.g., rss:///../job.cache), letting a remote IPP client write RSS XML bytes outside CacheDir/rss. Because CacheDir is group-writable by default, the notifier (running as lp) can overwrite root-managed state files via temp-file + rename(), leading to job cache corruption and loss of queued jobs after restart.
Apply upstream fix to prevent path traversal in RSS notifier. Reference: [ https://nvd.nist.gov/vuln/detail/CVE-2026-34978 ] Signed-off-by: Abhishek Bachiphale <[email protected]> --- meta/recipes-extended/cups/cups.inc | 1 + .../cups/cups/CVE-2026-34978.patch | 120 ++++++++++++++++++ 2 files changed, 121 insertions(+) create mode 100644 meta/recipes-extended/cups/cups/CVE-2026-34978.patch diff --git a/meta/recipes-extended/cups/cups.inc b/meta/recipes-extended/cups/cups.inc index 2724ce72fb..e739cfa579 100644 --- a/meta/recipes-extended/cups/cups.inc +++ b/meta/recipes-extended/cups/cups.inc @@ -15,6 +15,7 @@ SRC_URI = "${GITHUB_BASE_URI}/download/v${PV}/cups-${PV}-source.tar.gz \ file://0004-cups-fix-multilib-install-file-conflicts.patch \ file://volatiles.99_cups \ file://cups-volatiles.conf \ + file://CVE-2026-34978.patch \ " GITHUB_BASE_URI = "https://github.com/OpenPrinting/cups/releases"; diff --git a/meta/recipes-extended/cups/cups/CVE-2026-34978.patch b/meta/recipes-extended/cups/cups/CVE-2026-34978.patch new file mode 100644 index 0000000000..043cab86ea --- /dev/null +++ b/meta/recipes-extended/cups/cups/CVE-2026-34978.patch @@ -0,0 +1,120 @@ +From 730347c5bbd5e1271149c6739aa858c0c83a7568 Mon Sep 17 00:00:00 2001 +From: Michael R Sweet <[email protected]> +Date: Tue, 31 Mar 2026 14:18:26 -0400 +Subject: [PATCH] Fix RSS notifier. + +OpenPrinting CUPS is an open source printing system for Linux and other +Unix-like operating systems. In versions 2.4.16 and prior, the RSS +notifier allows .. path traversal in notify-recipient-uri (e.g., +rss:///../job.cache), letting a remote IPP client write RSS XML bytes +outside CacheDir/rss (anywhere that is lp-writable). In particular, +because CacheDir is group-writable by default (typically root:lp and +mode 0770), the notifier (running as lp) can replace root-managed state +files via temp-file + rename(). This PoC clobbers CacheDir/job.cache +with RSS XML, and after restarting cupsd the scheduler fails to parse +the job cache and previously queued jobs disappear. + +CVE: CVE-2026-34978 + +Upstream-Status: Backport [ https://github.com/OpenPrinting/cups/commit/730347c5bbd5e1271149c6739aa858c0c83a7568 ] + +Signed-off-by: Abhishek Bachiphale <[email protected]> + +--- + notifier/rss.c | 20 ++++++++++++++------ + scheduler/ipp.c | 14 +++++++++++++- + 3 files changed, 29 insertions(+), 7 deletions(-) + +diff --git a/notifier/rss.c b/notifier/rss.c +index f17e1494c6..250ad877e7 100644 +--- a/notifier/rss.c ++++ b/notifier/rss.c +@@ -1,11 +1,12 @@ + /* + * RSS notifier for CUPS. + * +- * Copyright © 2020-2024 by OpenPrinting. +- * Copyright 2007-2015 by Apple Inc. +- * Copyright 2007 by Easy Software Products. ++ * Copyright © 2020-2026 by OpenPrinting. ++ * Copyright © 2007-2015 by Apple Inc. ++ * Copyright © 2007 by Easy Software Products. + * +- * Licensed under Apache License v2.0. See the file "LICENSE" for more information. ++ * Licensed under Apache License v2.0. See the file "LICENSE" for more ++ * information. + */ + + /* +@@ -80,6 +81,7 @@ main(int argc, /* I - Number of command-line arguments */ + http_status_t status; /* HTTP GET/PUT status code */ + char filename[1024], /* Local filename */ + newname[1024]; /* filename.N */ ++ struct stat fileinfo; /* Local file information */ + cups_lang_t *language; /* Language information */ + ipp_attribute_t *printer_up_time, /* Timestamp on event */ + *notify_sequence_number,/* Sequence number */ +@@ -111,9 +113,9 @@ main(int argc, /* I - Number of command-line arguments */ + + if (httpSeparateURI(HTTP_URI_CODING_ALL, argv[1], scheme, sizeof(scheme), + username, sizeof(username), host, sizeof(host), &port, +- resource, sizeof(resource)) < HTTP_URI_OK) ++ resource, sizeof(resource)) < HTTP_URI_OK || strstr(resource, "../") != NULL) + { +- fprintf(stderr, "ERROR: Bad RSS URI \"%s\"!\n", argv[1]); ++ fprintf(stderr, "ERROR: Bad RSS URI \"%s\".\n", argv[1]); + return (1); + } + +@@ -209,6 +211,12 @@ main(int argc, /* I - Number of command-line arguments */ + snprintf(filename, sizeof(filename), "%s/rss%s", cachedir, resource); + snprintf(newname, sizeof(newname), "%s.N", filename); + ++ if (!lstat(filename, &fileinfo) && !S_ISREG(fileinfo.st_mode)) ++ { ++ fprintf(stderr, "ERROR: Local RSS path \"%s\" is not a file.\n", filename); ++ return (1); ++ } ++ + httpAssembleURIf(HTTP_URI_CODING_ALL, baseurl, sizeof(baseurl), "http", + NULL, server_name, atoi(server_port), "/rss%s", resource); + } +diff --git a/scheduler/ipp.c b/scheduler/ipp.c +index 174871741b..cb228b87c8 100644 +--- a/scheduler/ipp.c ++++ b/scheduler/ipp.c +@@ -1,7 +1,7 @@ + /* + * IPP routines for the CUPS scheduler. + * +- * Copyright © 2020-2025 by OpenPrinting ++ * Copyright © 2020-2026 by OpenPrinting + * Copyright © 2007-2021 by Apple Inc. + * Copyright © 1997-2007 by Easy Software Products, all rights reserved. + * +@@ -1997,6 +1997,12 @@ add_job_subscriptions( + "notify-status-code", IPP_ATTRIBUTES); + return; + } ++ else if (!strcmp(scheme, "rss") && strstr(resource, "../") != NULL) ++ { ++ send_ipp_status(con, IPP_STATUS_ERROR_NOT_POSSIBLE, _("Bad notify-recipient-uri URI \"%s\"."), recipient); ++ ippAddInteger(con->response, IPP_TAG_SUBSCRIPTION, IPP_TAG_ENUM, "notify-status-code", IPP_STATUS_ERROR_ATTRIBUTES_OR_VALUES); ++ return; ++ } + } + else if (!strcmp(attr->name, "notify-pull-method") && + attr->value_tag == IPP_TAG_KEYWORD) +@@ -6067,6 +6073,12 @@ create_subscriptions( + "notify-status-code", IPP_ATTRIBUTES); + return; + } ++ else if (!strcmp(scheme, "rss") && strstr(resource, "../") != NULL) ++ { ++ send_ipp_status(con, IPP_STATUS_ERROR_NOT_POSSIBLE, _("Bad notify-recipient-uri URI \"%s\"."), recipient); ++ ippAddInteger(con->response, IPP_TAG_SUBSCRIPTION, IPP_TAG_ENUM, "notify-status-code", IPP_STATUS_ERROR_ATTRIBUTES_OR_VALUES); ++ return; ++ } + } + else if (!strcmp(attr->name, "notify-pull-method") && + attr->value_tag == IPP_TAG_KEYWORD) -- 2.40.0
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