{"schema_version":"1.7.5","id":"CURL-CVE-2021-22925","published":"2021-07-21T08:00:00Z","modified":"2026-05-27T02:29:25.274707Z","aliases":["CVE-2021-22925"],"summary":"TELNET stack contents disclosure again","details":"curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS`\nin libcurl. This rarely used option is used to send variable=content pairs to\nTELNET servers.\n\nDue to flaw in the option parser for sending `NEW_ENV` variables, libcurl\ncould be made to pass on uninitialized data from a stack based buffer to the\nserver. Therefore potentially revealing sensitive internal information to the\nserver using a clear-text network protocol.\n\nThis could happen because curl did not call and use `sscanf()` correctly when\nparsing the string provided by the application.\n\nThe previous curl security vulnerability\n[CVE-2021-22898](https://curl.se/docs/CVE-2021-22898.html) is almost identical\nto this one but the fix was insufficient so this security vulnerability\nremained.","affected":[{"ranges":[{"type":"SEMVER","events":[{"introduced":"7.7"},{"fixed":"7.78.0"}]},{"type":"GIT","repo":"https://github.com/curl/curl.git","events":[{"introduced":"a1d6ad26100bc493c7b04f1301b1634b7f5aa8b4"},{"fixed":"894f6ec730597eb243618d33cc84d71add8d6a8a"}]}],"versions":["7.77.0","7.76.1","7.76.0","7.75.0","7.74.0","7.73.0","7.72.0","7.71.1","7.71.0","7.70.0","7.69.1","7.69.0","7.68.0","7.67.0","7.66.0","7.65.3","7.65.2","7.65.1","7.65.0","7.64.1","7.64.0","7.63.0","7.62.0","7.61.1","7.61.0","7.60.0","7.59.0","7.58.0","7.57.0","7.56.1","7.56.0","7.55.1","7.55.0","7.54.1","7.54.0","7.53.1","7.53.0","7.52.1","7.52.0","7.51.0","7.50.3","7.50.2","7.50.1","7.50.0","7.49.1","7.49.0","7.48.0","7.47.1","7.47.0","7.46.0","7.45.0","7.44.0","7.43.0","7.42.1","7.42.0","7.41.0","7.40.0","7.39.0","7.38.0","7.37.1","7.37.0","7.36.0","7.35.0","7.34.0","7.33.0","7.32.0","7.31.0","7.30.0","7.29.0","7.28.1","7.28.0","7.27.0","7.26.0","7.25.0","7.24.0","7.23.1","7.23.0","7.22.0","7.21.7","7.21.6","7.21.5","7.21.4","7.21.3","7.21.2","7.21.1","7.21.0","7.20.1","7.20.0","7.19.7","7.19.6","7.19.5","7.19.4","7.19.3","7.19.2","7.19.1","7.19.0","7.18.2","7.18.1","7.18.0","7.17.1","7.17.0","7.16.4","7.16.3","7.16.2","7.16.1","7.16.0","7.15.5","7.15.4","7.15.3","7.15.2","7.15.1","7.15.0","7.14.1","7.14.0","7.13.2","7.13.1","7.13.0","7.12.3","7.12.2","7.12.1","7.12.0","7.11.2","7.11.1","7.11.0","7.10.8","7.10.7","7.10.6","7.10.5","7.10.4","7.10.3","7.10.2","7.10.1","7.10","7.9.8","7.9.7","7.9.6","7.9.5","7.9.4","7.9.3","7.9.2","7.9.1","7.9","7.8.1","7.8","7.7.3","7.7.2","7.7.1","7.7","curl-7_77_0","curl-7_76_1","curl-7_76_0","curl-7_75_0","curl-7_74_0","curl-7_73_0","tiny-curl-7_72_0","curl-7_72_0","curl-7_71_1","curl-7_71_0","curl-7_70_0","curl-7_69_1","curl-7_69_0","curl-7_68_0","curl-7_67_0","curl-7_66_0","curl-7_65_3","curl-7_65_2","curl-7_65_1","curl-7_65_0","curl-7_64_1","curl-7_64_0","curl-7_63_0","curl-7_62_0","curl-7_61_1","curl-7_61_0","curl-7_60_0","curl-7_59_0","curl-7_58_0","curl-7_57_0","curl-7_56_1","curl-7_56_0","curl-7_55_1","curl-7_55_0","curl-7_54_1","curl-7_54_0","curl-7_53_1","curl-7_53_0","curl-7_52_1","curl-7_52_0","curl-7_51_0","curl-7_50_3","curl-7_50_2","curl-7_50_1","curl-7_50_0","curl-7_49_1","curl-7_49_0","curl-7_48_0","curl-7_47_1","curl-7_47_0","curl-7_46_0","curl-7_45_0","curl-7_44_0","curl-7_43_0","curl-7_42_1","curl-7_42_0","curl-7_41_0","curl-7_40_0","curl-7_39_0","curl-7_38_0","curl-7_37_1","curl-7_37_0","curl-7_36_0","curl-7_35_0","curl-7_34_0","curl-7_33_0","curl-7_32_0","curl-7_31_0","curl-7_30_0","curl-7_29_0","curl-7_28_1","curl-7_28_0","curl-7_27_0","curl-7_26_0","curl-7_25_0","curl-7_24_0","curl-7_23_1","curl-7_23_0","curl-7_22_0","curl-7_21_7","curl-7_21_6","curl-7_21_5","curl-7_21_4","curl-7_21_3","curl-7_21_2","curl-7_21_1","curl-7_21_0","curl-7_20_1","curl-7_20_0","curl-7_19_7","curl-7_19_6","curl-7_19_5","curl-7_19_4","curl-7_19_3","curl-7_19_2","curl-7_19_1","curl-7_19_0","curl-7_18_2","curl-7_18_1","curl-7_18_0","curl-7_17_1","curl-7_17_0","curl-7_17_0-preldapfix","curl-7_16_4","curl-7_16_3","curl-7_16_2","curl-7_16_1","curl-7_16_0","curl-7_15_6-prepipeline","curl-7_15_5","curl-7_15_4","curl-7_15_3","curl-7_15_2","curl-7_15_1","curl-7_15_0","curl-7_14_1","curl-7_14_0","curl-7_13_2","curl-7_13_1","before_ftp_statemachine","curl-7_13_0","curl-7_12_3","curl-7_12_2","curl-7_12_1","curl-7_12_0","curl-7_11_2","curl-7_11_1","curl-7_11_0","curl-7_10_8","curl-7_10_7","curl-7_10_6","curl-7_10_5","curl-7_10_4","curl-7_10_3","curl-7_10_2","curl-7_10_1","curl-7_10","curl-7_9_8","curl-7_9_7","curl-7_9_7-pre2","curl-7_9_6","curl-7_9_5","curl-7_9_5-pre4","curl-7_9_5-pre2","curl-7_9_4","curl-7_9_3","curl-7_9_3-pre3","curl-7_9_3-pre2","curl-7_9_3-pre1","curl-7_9_2","curl-7_9_1","curl-7_9","before_urldata_rename","curl-7_8_1","curl-7_8_1-pre3","curl-7_8","curl-7_8-pre2","curl-7_7_3","curl-7_7_2","curl-7_7_1","curl-7_7","curl-7_7-beta5","curl-7_7-beta3","curl-7_7-beta2","curl-7_7-beta1","curl-7_7_alpha2"],"database_specific":{"source":"https://curl.se/docs/CURL-CVE-2021-22925.json","vanir_signatures":[{"deprecated":false,"digest":{"function_hash":"316933520917559347077501990993139660214","length":2162},"id":"CURL-CVE-2021-22925-42b460d0","signature_type":"Function","signature_version":"v1","source":"https://github.com/curl/curl.git/commit/894f6ec730597eb243618d33cc84d71add8d6a8a","target":{"file":"lib/telnet.c","function":"suboption"}},{"deprecated":false,"digest":{"line_hashes":["73371219997613798860273049430938336872","246464346227486228829190896668526825182","211103125117598029027713563117906999281","45302255415263079241276111190376578806","66444213479799562148186156236093836400","171170274092991383111325095799231300614","269634034906769680142597048279449049406","89712093938542999602004345946193224210","263138597271543149838825752148738172629"],"threshold":0.9},"id":"CURL-CVE-2021-22925-6cb4958a","signature_type":"Line","signature_version":"v1","source":"https://gith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of Uninitialized Variable","id":"CWE-457"},"URL":"https://curl.se/docs/CVE-2021-22925.json","affects":"both","award":{"amount":"800","currency":"USD"},"issue":"https://hackerone.com/reports/1223882","last_affected":"7.77.0","package":"curl","severity":"Medium","www":"https://curl.se/docs/CVE-2021-22925.html"},"credits":[{"name":"Red Hat Product Security","type":"FINDER"},{"name":"Red Hat Product Security","type":"REMEDIATION_DEVELOPER"}]}